How to put six coins together

Step 1: Prepare six coins (for the sake of intuition, you can choose a larger coin).

Step 2: Arrange four coins of the same size at the four corners of a regular shape, and put the largest coin in the middle to form a cross.

Step 3: put the last coin on the largest coin in the middle, so that no matter which direction you look at it, the three coins connected in a line and the overlapping one are all four coins.