Reversing Arrow Illusion
Draw two parallel arrows on a piece of paper. Fill a glass with water halfway through. Place the paper behind the glass in such a way that one arrow is below the water level and the other arrow above it. Look at the arrows through the glass. The arrow below the water level appears inverted!!
An inverted image is formed in the converging lens when the object is at a distance greater than the focal distance. The glass with water acts as a convergent lens, thus creating inverted the image of the arrow we designed.