Anyone who's ever sat in the low-slung seat of an Adirondack chair and sunk into the curve of the fanned back knows there's no cushion-free seat like it. You'll see how some of the parts do double duty, making it a simple build. The beefy seat supports are also the back legs; the wide armrests also hold the back support. Assembling a basic one will take less than a day.
See How to Build an Adirondack Chair
for full step-by-step instructions.