Images having a transparent background can be easily stacked ... but once you release the mouse button, the outline disappears. Once the selection is complete, right-click on the selection area.

In addition, if you add an Alpha channel to your image, you can remove the area surrounding your selection and replace it with a transparent background ... the left mouse button as you move ...

A food dye that helps give certain sodas and snacks their hallmark orange hue renders mouse skin almost completely ... can temporarily turn biological tissue transparent to the naked eye, as ...

NPR's Juana Summers talks with Regina Barber and Emily Kwong of Short Wave about "scuba-diving" lizards, a trick to turn a mouse's skin transparent and whether finger counting helps kids' math skills.