A Quirk of Fluid Dynamics Causes Shapes to Invert Themselves

Here ’s a nerveless scene of mobile dynamics that you might not have think of before : When a shape is pushed into the weewee , it make a blank in its viewing . As the space crumble , the figure inverts itself .

This is cool ! When a shape like a star is pushed into a fluid , the “ points ” on the star collapse inwards quickly and become the holler of the headliner , and the hollows give tardily and become point .

This is cooler . When the curves get sharp enough , as they do with the “ star ” towards the end of the video recording , the inverted contour re - inverts itself , and the original star “ reemerges . ”