See Video Below:Description: This classic illusion, made famous by psychologist Joseph Jastrow, is elegantly revisited here by Father Alex.  The magician presents two wooden school rulers: one marked in centimeters, the other marked in inches.  He explains that the imperial system is decidedly mysterious for a French person... and immediately proves it:  Placed side by side, 15 cm seem to be equal to 6 inches.  By simply reversing the position of the rulers, not only do they visually change in size, but this time 7 inches appear to correspond to 9 cm.  To conclude, the magician reveals that the two rulers are in fact exactly the same length.  A strong, clear, and immediate visual illusion that never fails to surprise and delight.  Contents  A beautiful wooden box, specially crafted for this effect  Two wooden rulers: one marked in centimeters, one marked in inches  An instructional video in French, in which Father Alex explains the principle behind the trick