This example is an 18" "shoe stool" made for walk in closets to be used while putting on socks and shoes.
While this example has stretchers, they are not recommended to allow for more leg movement.
The example seat is made of highly figured walnut which has to be specially sourced. Almost any wood can be ordered and specialty woods acquired.
Stool parts are made on the lathe. Slots are cut into the tops of the legs and once inserted through the seat, contrasting hardwood wedges are hammered into the slot locking it in place.