Ink and pencil

Phil Taylor (effectrode)

Artist's deviantART profile http://effectrode.deviantart.com.

Impossible cog (gear) wheel 3
Impossible cog (gear) wheel 3

Impossible cog (gear) wheel 4
Impossible cog (gear) wheel 4

Impossible cog (gear) wheel 6
Impossible cog (gear) wheel 3

See also rendering of this impossible gear wheel.

Images were found at