> I think some choices in Euclidea are too restrictive (e.g. collapsible compass, inability to draw arcs). Collapsible compass is not a choice of Euclidea, but

> I think some choices in Euclidea are too restrictive (e.g. collapsible compass, inability to draw arcs). Collapsible compass is not a choice of Euclidea, but a choice of Euclid. (Although, of course, one of the first things Euclid proves is that you can simulate a rigid compass with a collapsible compass: https://en.wikipedia.org/wiki/Compass_equivalence_theorem https://en.wikipedia.org/wiki/Compass_equivalence_theorem.)