Puzzle #1

Puzzle #1

May 18, 2007

Since I am a big fan of puzzles, I will try to post here from time to time a few digital design related puzzles.

This particular one was given to me in an interview at IBM over 10 years ago.

Due to the war in the land of Logicia there is a shortage of XOR gates. Unfortunately, the only logic gates available are two weird components called “X” and “Y”. The truth table of both components is presented below - Z represents a High-Z value on the output.
Could you help the poor engineers of Logicia to build an XOR gate?