This was as foolproof a plan as she'd ever come up with.

With this cart I have developed an even better and more foolproof plan.

It was a foolproof plan, right up until the moment an arm shot out from behind the corner and clotheslined him.

My months of strategy are over, and we have a foolproof plan.

It wasn't the most foolproof plan in the world, but no operation was ever one hundred percent airtight.

Any fool could try to come up with a foolproof plan.

But first he needed time to formulate a foolproof plan.

That being the case, there simply wasn't any time to come up with the sort of elaborate, foolproof plan they might otherwise have envisioned.

"Only an idiot would say no to such a foolproof plan."

If we go this route, a foolproof plan must be made.