Just how much can a pheromone-enabled swarm do? Motivated by robotic construction, we set out to show that a swarm of computationally simple ants, communicating only via pheromones, can in fact perform classic compass-straightedge geometry, and thus can make many shapes and perform many nontrivial geometric tasks. The ants do not need specially-designed stigmergic building materials, a prepared environment, local or global direct communication facilities (such as radio or line-of-sight signaling), or any localization beyond initial starting points for drawing. We describe the proof of concept in replicable detail. We then note that its accuracy and efficiency can be greatly improved through augmentation with a simple embeddable broadcast mechanism.