Pull yourself up by your own hands! Lick your own scalp with your tongue! Those seemingly impossible tasks in the real world have all become reality in M.C. ESCHER's works. Long-time readers of Reader's Digest must be familiar with these pictures, which originally came mostly from M.C. ESCHER. There are great mysteries in small illustrations, which are hard to see at a glance. Without serious thinking and analysis, you will often be deceived by them.