A ‘three-sided die’ (or, more properly, a d3) is quite easy to construct, actually. Simply label a twelve-sided die such that four of the faces say ‘1’, four say ‘2’, and four say ‘3’. (Similar to this twelve-sided d4.)
Another easy option for rolling a N-sided die is a N-sided prism, like a pencil that you roll on the table that can only come to rest on one of N sides (and never on the tips). With 3 sides it becomes a triangular prism that doesn’t quite roll as well as we’d like, but it’s doable.
Yet another option is a spinning top with N faces, where you can set N to whatever you want that’s >= 3.
But you’re right that in practice, probably re-labeling an existing dice, like relabeling a d6 as [1,1,2,2,3,3], is easiest.
A ‘three-sided die’ (or, more properly, a d3) is quite easy to construct, actually. Simply label a twelve-sided die such that four of the faces say ‘1’, four say ‘2’, and four say ‘3’. (Similar to this twelve-sided d4.)
Another easy option for rolling a N-sided die is a N-sided prism, like a pencil that you roll on the table that can only come to rest on one of N sides (and never on the tips). With 3 sides it becomes a triangular prism that doesn’t quite roll as well as we’d like, but it’s doable.
Yet another option is a spinning top with N faces, where you can set N to whatever you want that’s >= 3.
But you’re right that in practice, probably re-labeling an existing dice, like relabeling a d6 as [1,1,2,2,3,3], is easiest.
Or this product http://spielpro.com/d3-by-the-dice-lab/