Python program resembling how I pile my socks.

sockpile.py

import random

# Each colour of sock represented by an integer.
socks = 2 * range(20)
# Randomize the order of our socks.
random.shuffle(socks)

# Container variable for our sorted socks and working stack.
sorted = []
stack = []

# Iterate over the unsorted socks one by one.
for sock in socks:
    if sock in stack:
        # If we have a matching sock already picked add them to our
        # sorted socks.
        stack.remove(sock)
        sorted.append(sock)
    else:
        # Otherwise place the sock in our sorting stack.
        stack.append(sock)
    # Print a per sock representation of our sorting procedure.
    print 'Stack:', stack
    print 'Sorted:', sorted