Imagine you have a 4 x 2 blue lego, a 4 x 2 red lego and a 2 x 2 yellow lego. How many ways, excluding rotations, can you put the legos together (you must use all the pieces)?

Yellow can attach to either other color 4 ways. Red and blue can connect 7 ways. So for each of those 7 ways, there are 4 ways the yellow can attach in a yellow, blue, red stack. that is 28. yellow, red, blue makes another 28. blue, red yellow 28. red, blue, yellow 28. that is 112 so far. Blue, yellow, red has 28. Red, yellow, blue also has 28. so that is 168.

Posted by William on 2007-07-09 03:08:51