diff --git a/README.md b/README.md
index 0820bd0..5a14dec 100644
--- a/README.md
+++ b/README.md
@@ -1,16 +1,18 @@
-# Stupid Worm Languag
-- program space is an arbitrary sized grid
-- the worm starts where you place the worm head @
-- as it passes over commands, they get moved to the back of the worm
-- values get pushed to stack (eaten) when passed over, worm body length increases
-- the program gets rearranged every time the worm executes it
+# sandworm
+program space is an arbitrary sized grid
+the worm starts where you place the worm head @
+as it passes over commands, they get moved to the back of the worm (also depending on the worm length)
+commands to change direction <>^v
+values get pushed to stack (eaten) when passed over, worm body length increases
+autosarkophagy/self-cannibalism is possible, cutting off the back of the worm (the lower part of the stack) and pushing the passed value to the stack (front of worm)
+conditional: pop then side/forward if top of stack is zero
 
 ## commands
 ```
 +- pop 2 values *, push sum/difference (uses the order they are popped, so `0 -` negates the top of the stack)
 ><^v change direction
-0..9 push number to stack
-/\ pop stack, reflect to the side if not zero
+0123456789ABCDEF push number to stack
+/\ pop stack, reflect to the side if zero
 ? reads one byte of input
 = duplicate top of stack
 ! pop and write output as ascii char
diff --git a/src/main.rs b/src/main.rs
index 41b3570..ae86212 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -159,19 +159,20 @@ impl SandWormInterpreter {
 				self.worm_in.push(instruction - 48);
 				dont_push_instruction = true;
 			}
+			// b'0'..=b'9' => self.grow(instruction - 48),
 			b'+' => {
 				let a = self.shrink();
 				self.worm_out.push(instruction);
 				let b = self.shrink();
 				dont_push_instruction = true;
-				self.worm_in.push(a.wrapping_add(b));
+				self.worm_in.push(a + b);
 			}
 			b'-' => {
 				let a = self.shrink();
 				self.worm_out.push(instruction);
 				dont_push_instruction = true;
 				let b = self.shrink();
-				self.worm_in.push(a.wrapping_sub(b));
+				self.worm_in.push(a + b);
 			}
 			b'v' => self.direction = Direction::Down,
 			b'^' => self.direction = Direction::Up,