Three Block Towers Poster
There are six possible towers with a red, blue and yellow block:
red on top, blue in the middle, yellow on the bottom
red on top, yellow in the middle, blue on the bottom
blue on top, yellow in the middle, red on the bottom
blue on top, red in the middle, yellow on the bottom
yellow on top, red in the middle, blue on the bottom
yellow on top, blue in the middle, red on the bottom
If you add a green block as well, there are 24 possibilities:
red, blue, yellow, green
red, blue, green, yellow
red, yellow, green, blue
red, yellow, blue, green
red, green, yellow, blue
red, green, blue, yellow
blue, yellow, green, red
blue, yellow, red, green
blue, green, yellow, red
blue, green, red, yellow
blue, red, yellow, green
blue, red, green, yellow
yellow, green, red, blue
yellow, green, blue, red
yellow, red, blue, green
yellow, red, green, blue
yellow, blue, green, red
yellow, blue, red, green
green, yellow, blue, red
green, yellow, red, blue
green, blue, red, yellow
green, blue, yellow, red
green, red, blue, yellow
green, red, yellow, blue