Usually, yes. This one is effectively a d6 (a cube), but two of the flat faces have been replaced by curves that connect opposite flat faces. As such you’ve got four flat faces that the die can actually stop on. If you ignore the curved parts but consider all of the flats to be separate faces, it’s a d4. If you consider two flats connected by a curve to be a single face altogether, it’s a d2.
Usually, yes. This one is effectively a d6 (a cube), but two of the flat faces have been replaced by curves that connect opposite flat faces. As such you’ve got four flat faces that the die can actually stop on. If you ignore the curved parts but consider all of the flats to be separate faces, it’s a d4. If you consider two flats connected by a curve to be a single face altogether, it’s a d2.