OK, this is another die. But this one looks like a coin.
Actually this is a double coin (similar to the Double D6).
It look like a bimetallic coin (such as the 1 or 2€ coin).
It is made of two parts that can move freely around one axis.
The external part shows 0 or 1 dot and the internal part shows 1 or 3 dots.
All the combinations give the numbers from 1 to 4.
(here the coin is in Grey Strong and Flexible and the dots have been inked with a white gel pen)
You have to launch it properly to make the internal part roll inside the external part while the double-coin is in the air. At this condition, this die is fair and behaves like a regular D4.
In theory, a die of any power of 2 (2, 4, 8, 16 etc.) could be done with this method.
This model is quite big so that the axis can be hidden into the thickness of the coin.
The 4 dots form a tetrahedron to underline it is equivalent to a D4.