You can't order a single ant, you only paint the scent, and the colony decides whether to follow.
Paint a pheromone field across the grid. Each tick the ants climb that field, toward food when foraging, back toward the nest when carrying, and lay a little scent of their own as they walk, while the whole field slowly evaporates. Every load of food carried home counts toward your score. Reach the goal before the timer expires.
Ants coordinate by stigmergy — indirect coordination through traces left in the environment, where one individual's mark prompts the next one's action. The same principle became a real optimisation method in ant colony algorithms.
The original design gives you the field rather than the ants. You paint the pheromone; they climb it, lay scent of their own, and the whole field evaporates slowly.
Steering the environment instead of the creatures is what makes it faithful to the thing it models. No ant is ever commanded, and your painted field is only a suggestion the colony partly overwrites — so a good solution has to survive the colony's own reinforcement of it.
Pheromone Painter is an original indirect-control simulation puzzle about steering a colony through the environment rather than the creatures. A free browser game made in-house at PlayPendium.