Ink and pencil
Mark Empire (empire539)
All basic impossible figures - Penrose tribar, Devil's fork, endless staircase and crazy crate - are used in this pencil sketch
Artist's deviantART profile http://empire539.deviantart.com.
Chateau Impossible
The image was found at http://empire539.deviantart.com/art/DSBA2b-Chateau-Impossible-257687504.