By counting each brick height as 3 plates and then adding other plates we can come up with a variety of combinations. If the sum of our stack of plates is a number that can be divided by 5 we can insert a pin in the beam we place on top of it.

Using these simple rules what other "pinnable" brick and plate combinations can you come up with? Try using longer support beams and shorter plates.

Which one of the stacks above is the best design and why?

Now building strong structures is just a matter of following the rules.