1. The girl on the chair looks back.
2. The girl in the chair looks back.
3. The girl at the chair looks back.
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Does #1 mean #2? Can we use the preposition 'at' before the chair?
What is the difference between #1 and #2? According to the shape of the chair, do we have to use either 'on' or 'in'?
Only #2 is correct if you mean she is sitting in the chair.
If you mean she's standing on the seat of the chair, that's #1,
If you mean she's standing next to the chair, that's #3.