OK, based on where the feet/legs are located, I'm guessing some sort of inchworm.

Understood: I was told it was found in a patio slat. :) I'll ask what sort of trees/shrubs were in the immediate vicinity. TY!

DD says the worm dropped down from what they believe is a Chinese elm tree (new house -- tree came with).

Could be a carpenter worm. They are pests of Chinese elm. Carpenter worm

Thanks so much for the ID and information, lgteacher! I'll pass on the fact sheet and have DD watch for worrisome signs.

If it were green, I'd call it a tomato worm.

javiwa, your initial observation about the legs was very astute. If indeed these caterpillars have just 5 pair of legs (3 up front and 2 near the read end) and they have the distinct movements of inchworms (arched backs and "standing" on the rear legs with the head and body suspended), then they are in the moth family Geometridae.

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jemdandy: Many caterpillar species are green and individual species can have various base colors depending on what they are eating. The above caterpillar is not a sphinx moth caterpillar, some of those are referred to as "tomato hornworms".