Cross Pins

The Cross pin is one of those very strange yet very lovely tactics.  I find them strange because either they aren't planned in advance and the position just accidentally occurs or they are planned and such planning calls for incredibly original thinking.

Here are a couple examples winnowed from Chernev's Combinations: The Heart of Chess.

Judging from White's first move, this Cross Pin was anticipated and not accidental

This Cross Pin actually has two variations, in order to avoid the mating combination in the first variation, White finds himself in a Cross Pin

The Cross Pin: