diff --git a/benchmarks/core/rot13.bril b/benchmarks/core/rot13.bril
new file mode 100644
index 000000000..ee1dc3cf0
--- /dev/null
+++ b/benchmarks/core/rot13.bril
@@ -0,0 +1,17 @@
+# ARGS: 10
+# Compute the char shifted forward by 13 (0-indexed)
+@main(input: int) {
+  aed: int = call @rot input;
+  print aed;
+}
+@rot(n: int):int{
+  thirteen: int = const 13;
+  twenty_six: int = const 26;
+  shifted: int = add n thirteen;
+  over: bool = ge shifted twenty_six;
+  br over .if .else;
+.if:
+  shifted: int = sub shifted twenty_six;
+.else:
+  ret shifted;
+}
diff --git a/benchmarks/core/rot13.out b/benchmarks/core/rot13.out
new file mode 100644
index 000000000..409940768
--- /dev/null
+++ b/benchmarks/core/rot13.out
@@ -0,0 +1 @@
+23
diff --git a/benchmarks/core/rot13.prof b/benchmarks/core/rot13.prof
new file mode 100644
index 000000000..c1c0cab70
--- /dev/null
+++ b/benchmarks/core/rot13.prof
@@ -0,0 +1 @@
+total_dyn_inst: 8
diff --git a/cs6120/lesson_2/ackermann.json b/cs6120/lesson_2/ackermann.json
new file mode 100644
index 000000000..40a981a50
--- /dev/null
+++ b/cs6120/lesson_2/ackermann.json
@@ -0,0 +1,205 @@
+{
+  "functions": [
+    {
+      "args": [
+        {
+          "name": "m",
+          "type": "int"
+        },
+        {
+          "name": "n",
+          "type": "int"
+        }
+      ],
+      "instrs": [
+        {
+          "dest": "zero",
+          "op": "const",
+          "type": "int",
+          "value": 0
+        },
+        {
+          "dest": "one",
+          "op": "const",
+          "type": "int",
+          "value": 1
+        },
+        {
+          "args": [
+            "m",
+            "zero"
+          ],
+          "dest": "cond_m",
+          "op": "eq",
+          "type": "bool"
+        },
+        {
+          "args": [
+            "cond_m"
+          ],
+          "labels": [
+            "m_zero",
+            "m_nonzero"
+          ],
+          "op": "br"
+        },
+        {
+          "label": "m_zero"
+        },
+        {
+          "args": [
+            "n",
+            "one"
+          ],
+          "dest": "tmp",
+          "op": "add",
+          "type": "int"
+        },
+        {
+          "args": [
+            "tmp"
+          ],
+          "op": "ret"
+        },
+        {
+          "label": "m_nonzero"
+        },
+        {
+          "args": [
+            "n",
+            "zero"
+          ],
+          "dest": "cond_n",
+          "op": "eq",
+          "type": "bool"
+        },
+        {
+          "args": [
+            "cond_n"
+          ],
+          "labels": [
+            "n_zero",
+            "n_nonzero"
+          ],
+          "op": "br"
+        },
+        {
+          "label": "n_zero"
+        },
+        {
+          "args": [
+            "m",
+            "one"
+          ],
+          "dest": "m1",
+          "op": "sub",
+          "type": "int"
+        },
+        {
+          "args": [
+            "m1",
+            "one"
+          ],
+          "dest": "tmp",
+          "funcs": [
+            "ack"
+          ],
+          "op": "call",
+          "type": "int"
+        },
+        {
+          "args": [
+            "tmp"
+          ],
+          "op": "ret"
+        },
+        {
+          "label": "n_nonzero"
+        },
+        {
+          "args": [
+            "m",
+            "one"
+          ],
+          "dest": "m1",
+          "op": "sub",
+          "type": "int"
+        },
+        {
+          "args": [
+            "n",
+            "one"
+          ],
+          "dest": "n1",
+          "op": "sub",
+          "type": "int"
+        },
+        {
+          "args": [
+            "m",
+            "n1"
+          ],
+          "dest": "t1",
+          "funcs": [
+            "ack"
+          ],
+          "op": "call",
+          "type": "int"
+        },
+        {
+          "args": [
+            "m1",
+            "t1"
+          ],
+          "dest": "t2",
+          "funcs": [
+            "ack"
+          ],
+          "op": "call",
+          "type": "int"
+        },
+        {
+          "args": [
+            "t2"
+          ],
+          "op": "ret"
+        }
+      ],
+      "name": "ack",
+      "type": "int"
+    },
+    {
+      "args": [
+        {
+          "name": "m",
+          "type": "int"
+        },
+        {
+          "name": "n",
+          "type": "int"
+        }
+      ],
+      "instrs": [
+        {
+          "args": [
+            "m",
+            "n"
+          ],
+          "dest": "tmp",
+          "funcs": [
+            "ack"
+          ],
+          "op": "call",
+          "type": "int"
+        },
+        {
+          "args": [
+            "tmp"
+          ],
+          "op": "print"
+        }
+      ],
+      "name": "main"
+    }
+  ]
+}
\ No newline at end of file
diff --git a/cs6120/lesson_2/ackermann.out b/cs6120/lesson_2/ackermann.out
new file mode 100644
index 000000000..015008f40
--- /dev/null
+++ b/cs6120/lesson_2/ackermann.out
@@ -0,0 +1,2 @@
+ack
+main
diff --git a/cs6120/lesson_2/blocks.py b/cs6120/lesson_2/blocks.py
new file mode 100644
index 000000000..effb7c833
--- /dev/null
+++ b/cs6120/lesson_2/blocks.py
@@ -0,0 +1,35 @@
+import json
+import sys
+
+terminators = ('br', 'jmp', 'ret')
+
+def blocks(filename):
+  with open(filename) as file:
+    program = json.load(file)
+    function = program["functions"][0]["instrs"]
+    cur_block = (None, [])
+    all_blocks = [cur_block]
+    for instr in function:
+      if "op" in instr:
+        cur_block[1].append(instr)
+        if(instr["op"] in terminators):
+          cur_block = (None, [])
+          all_blocks.append(cur_block)
+      else:
+        # blocks that are empty and have no labels can safely be removed 
+        if(len(cur_block[1]) == 0 and cur_block[0] == None):
+          all_blocks = all_blocks[:-1]
+        cur_block = (instr["label"], [])
+        all_blocks.append(cur_block)
+    # remove empty last block  
+    if(len(cur_block[1]) == 0 and cur_block[0] == None):
+          all_blocks = all_blocks[:-1]
+    return all_blocks
+  
+
+if __name__ == "__main__":
+  filename = sys.argv[1]
+  all_blocks = blocks(filename)
+  for (label, contents) in all_blocks:
+    print(label)
+    print(contents)
\ No newline at end of file
diff --git a/cs6120/lesson_2/branch_names.py b/cs6120/lesson_2/branch_names.py
new file mode 100644
index 000000000..4d603feed
--- /dev/null
+++ b/cs6120/lesson_2/branch_names.py
@@ -0,0 +1,9 @@
+import json
+import sys
+
+if __name__ == "__main__":
+  filename = sys.argv[1]
+  with open(filename) as file:
+    program = json.load(file)
+    for function in program["functions"]:
+      print(function["name"])
\ No newline at end of file
diff --git a/cs6120/lesson_2/cfg.py b/cs6120/lesson_2/cfg.py
new file mode 100644
index 000000000..872d6a0d0
--- /dev/null
+++ b/cs6120/lesson_2/cfg.py
@@ -0,0 +1,61 @@
+import sys
+import blocks
+    
+def change_labels(all_blocks):
+  new_name = "label "
+  new_num = 0
+  all_labels = [block[0] for block in all_blocks]
+  for i in range(len(all_labels)):
+    if(all_labels[i] == None):
+      while((new_name + str(new_num)) in all_labels):
+        new_num += 1
+      all_labels[i] = new_name + str(new_num)
+  
+  for i in range(len(all_blocks)):
+    all_blocks[i] = (all_labels[i], all_blocks[i][1])
+  return all_blocks
+
+def build_cfg(all_blocks):
+  successors = {"entry": [], "exit": []}
+  for block in all_blocks:
+    successors[block[0]] = []
+  # dummy entry block
+  successors["entry"] = [all_blocks[0][0]]
+  
+  for i in range(len(all_blocks)):
+    # last entry is ret -> successor = exit
+    # last entry is br -> successors = br targets
+    # last entry is jmp -> successor = jmp
+    # last entry is nothing -> successor = next block (or exit if last block)
+    last_entry = all_blocks[i][1][-1]
+    if(last_entry["op"] == "br" or last_entry["op"] == "jmp"):
+      successors[all_blocks[i][0]] = last_entry["labels"]
+    elif(last_entry["op"] == "ret"):
+      successors[all_blocks[i][0]] = ["exit"]
+    else:
+      if(i == len(all_blocks) - 1):
+        successors[all_blocks[i][0]] = ["exit"]
+      else:
+        successors[all_blocks[i][0]] = [all_blocks[i + 1][0]]  
+  return successors
+
+def remove_orphans(all_blocks, cfg):
+  visited = {}
+  for block in all_blocks:
+    visited[block[0]] = False
+    
+  for entry in cfg:
+    for successor in cfg[entry]:
+      visited[successor] = True 
+  
+  parsed_blocks = []
+  for block in all_blocks:
+    if visited[block[0]]:
+      parsed_blocks.append(block)
+  return parsed_blocks
+if __name__ == "__main__":
+  filename = sys.argv[1]
+  all_blocks = change_labels(blocks.blocks(filename))
+  cfg = build_cfg(all_blocks)
+  print(cfg)
+  # print(remove_orphans(all_blocks, cfg))
\ No newline at end of file
diff --git a/cs6120/lesson_2/empty.json b/cs6120/lesson_2/empty.json
new file mode 100644
index 000000000..2e6257de1
--- /dev/null
+++ b/cs6120/lesson_2/empty.json
@@ -0,0 +1,3 @@
+{
+  "functions": []
+}
\ No newline at end of file
diff --git a/cs6120/lesson_2/empty.out b/cs6120/lesson_2/empty.out
new file mode 100644
index 000000000..e69de29bb
diff --git a/cs6120/lesson_2/rot13.json b/cs6120/lesson_2/rot13.json
new file mode 100644
index 000000000..e850a195e
--- /dev/null
+++ b/cs6120/lesson_2/rot13.json
@@ -0,0 +1,105 @@
+{
+  "functions": [
+    {
+      "args": [
+        {
+          "name": "input",
+          "type": "int"
+        }
+      ],
+      "instrs": [
+        {
+          "args": [
+            "input"
+          ],
+          "dest": "aed",
+          "funcs": [
+            "rot"
+          ],
+          "op": "call",
+          "type": "int"
+        },
+        {
+          "args": [
+            "aed"
+          ],
+          "op": "print"
+        }
+      ],
+      "name": "main"
+    },
+    {
+      "args": [
+        {
+          "name": "n",
+          "type": "int"
+        }
+      ],
+      "instrs": [
+        {
+          "dest": "thirteen",
+          "op": "const",
+          "type": "int",
+          "value": 13
+        },
+        {
+          "dest": "twenty_six",
+          "op": "const",
+          "type": "int",
+          "value": 26
+        },
+        {
+          "args": [
+            "n",
+            "thirteen"
+          ],
+          "dest": "shifted",
+          "op": "add",
+          "type": "int"
+        },
+        {
+          "args": [
+            "shifted",
+            "twenty_six"
+          ],
+          "dest": "over",
+          "op": "ge",
+          "type": "bool"
+        },
+        {
+          "args": [
+            "over"
+          ],
+          "labels": [
+            "if",
+            "else"
+          ],
+          "op": "br"
+        },
+        {
+          "label": "if"
+        },
+        {
+          "args": [
+            "shifted",
+            "twenty_six"
+          ],
+          "dest": "shifted",
+          "op": "sub",
+          "type": "int"
+        },
+        {
+          "label": "else"
+        },
+        {
+          "args": [
+            "shifted"
+          ],
+          "op": "ret"
+        }
+      ],
+      "name": "rot",
+      "type": "int"
+    }
+  ]
+}
diff --git a/cs6120/lesson_2/rot13.out b/cs6120/lesson_2/rot13.out
new file mode 100644
index 000000000..8352bc362
--- /dev/null
+++ b/cs6120/lesson_2/rot13.out
@@ -0,0 +1,2 @@
+main
+rot
diff --git a/cs6120/lesson_2/turnt.toml b/cs6120/lesson_2/turnt.toml
new file mode 100644
index 000000000..ae693c7cc
--- /dev/null
+++ b/cs6120/lesson_2/turnt.toml
@@ -0,0 +1 @@
+command = "python branch_names.py {filename}"
\ No newline at end of file
diff --git a/docs/tools/bench.md b/docs/tools/bench.md
index 1634619d3..0bf3e0426 100644
--- a/docs/tools/bench.md
+++ b/docs/tools/bench.md
@@ -66,6 +66,7 @@ The current benchmarks are:
 * `fitsinside`: Output whether or not a rectangle fits inside of another rectangle given the width and height lengths.
 * `relative-primes`: Print all numbers relatively prime to *n* using [Euclidean algorithm][euclidean_into].
 * `riemann`: Prints the left, midpoint, and right [Riemann][riemann] Sums for a specified function, which is the square function in this benchmark.
+* `rot13`: Prints the [rot13][rot13] substitution of a character (represented as an integer in the range 0 to 25).
 * `sieve`: Print all prime numbers up to *n* using the [Sieve of Eratosthenes][sievee].
 * `sqrt`: Implements the [Newton–Raphson Method][newton] of approximating the square root of a number to arbitrary precision
 * `sum-bit`: Print the number of 1-bits in the binary representation of the input integer.
@@ -103,6 +104,7 @@ Credit for several of these benchmarks goes to Alexa VanHattum and Gregory Yaune
 [adler32]: https://en.wikipedia.org/wiki/Adler-32
 [uparrow]: https://en.wikipedia.org/wiki/Knuth%27s_up-arrow_notation
 [riemann]: https://en.wikipedia.org/wiki/Riemann_sum
+[rot13]: https://en.wikipedia.org/wiki/ROT13
 [primitive_root]: https://en.wikipedia.org/wiki/Primitive_root_modulo_n
 [mandelbrot]: https://en.wikipedia.org/wiki/Mandelbrot_set
 [palindrome]: https://en.wikipedia.org/wiki/Palindrome