Fork and spear!

Do  you the terms of fork and spear in chess? They are describing tactical weapons, which should be in our arsenal

1. The fork

Definition:

One piece attacks two other pieces or points simultaneous.

Well kown is the knight fork, but all all other pieces also can do the fork job

 2. the spear

Definition:

One piece attacks two pieces in a row, line or diagonale. The first attacked piece is the more valuable one.

Only queen, rook and bishop can do the spear job

Here now a puzzle, where fork and spear helped to execute a decisive blow

( hint: The spear is in move 3)