| Answer | Crossword Clue |
|---|---|
| PHI | ... phenomenon (optical illusion) |
| MIRAGE | Optical illusion |
| TRICK | Optical illusion |
| MIRAGE | Optical illusion. |
| GLASSEYE | Optical illusion |
| ESCHER | Optical illusion illustrator |
| TROMPE | ... l'oeil (optical illusion) |
| FATA | ... morgana (optical illusion) |
| ESCHER | Optical illusion artist |
| OEIL | Trompe l'... (optical illusion) |
| ESCHER | Optical illusion artist M.C. -- |
| ICOULDNTFIGURE | Start of an optical illusion quip |
| AORB | 'Which is longer, --?' (optical illusion question) |
