# Tutorial 4 Problem 3

# Write a recursive function printPattern(seed, depth) such that when we call it as
# follows: printPattern('a', 8), it produces the following output:
# aaaaaaaa
# bbbbbbb
# cccccc
# ddddd
# eeee
# fff
# gg
# h
# h
# gg
# fff
# eeee
# ddddd
# cccccc
# bbbbbbb
# aaaaaaaa

# Hint: Feel free to use the built-in functions ord('a'), which produces 97, and chr(97)
# which produces 'a'. Feel free to combine them.
# Why is the first parameter called ‘seed’?
# Answer: because it is used as the "seed", i.e., as the first value of the print pattern.
# Why is the second parameter called ‘depth’?
# Answer: because it is the "depth" of the recursion, i.e., the number of times the recursive
# function is called (# of stackframes)

def printPattern(seed, depth):
  if depth != 0: 
    print(seed*depth)
    printPattern(chr(ord(seed)+1), depth-1)
    print(seed*depth)
  return

# Main
printPattern('a', 8)
print()
printPattern('c', 10)