Think of four color blocks as A, B, C and D, and there are two ways to connect them. The first way is that A, B, C and D are connected in series.

* * * There are a (4 4,4)/2 =12 kinds. The second kind can be regarded as starting from A, that is, a-b, a-c and a-d, and there are obviously four kinds.

To sum up, you can see *** 16 kinds! Exactly, or the whole family will die