This circuit is full adder.
I think this circuit is limit to thin full adder.
Actually, my intention is get more simple and wide xor gate.
But, this circuit is my best simple xor and adder.

There are many experiment circuit my save file.
Please, give me your simple redstone xor gate.
And divulge me to upload save file, not MCEdit schematic.
I cannot find upload button.

Another Site
http://cafe.naver.com/minecraftkor.cafe?iframe_url=/ArticleRead.nhn%3Farticleid=250722&

Refer
http://en.wikipedia.org/wiki/XOR_gate