```
# Escape from Death Valley!
# Move by with a zigzag pattern using real modulo functions.
# This function returns a value from 0 to 15:
def mod15(n):
while n >= 15:
n -= 15
return n
# This function should return a value from 0 to 9:
def mod9(n):
# While n is greater or equal to 9, subtract 9 from n:
while n >= 9:
9-n
return n
# Don't change the following code:
while True:
time = hero.time
if time < 30:
y = 10 + 3 * mod15(time)
else:
y = 20 + 3 * mod9(time)
x = 10 + time
hero.moveXY(x, y)
```

This is my code for zig zag and zoom. But something keeps happening and the the third zig zag always fails and my hero gets stuck HELP!