4-sided DICE

Usually denoted by D4 and existing in pyramidal shape (also called tetrahedron or tetraeder), a kind of elongated pyramidal shape, wedge shape, 'stick' shape (also called 'log dice'), and a kind of elliptical shape (rugby ball) see roman 4-sided elliptical dice.

Below a few pyramidal transparent D4's ...

... and some unicolored ones ...

... and normal and tiny multicolored dice.

Usually the numbers are placed in the centers, sometimes in the corners.

D4's known as Crystal Dice and a wedge D4.

As an example of some rectangular dice sticks, also called 'log dice', these horn dice sticks. You can see more in DICE from NEPAL and DICE from INDIA

A modern D4 made of stainless steel 304, and a pair of 4-sided solid brass dice sticks, with 1, 2, 3, and 4 pips.