Parachute and elevator: what they have in common
Step 1.
Parachute
— has part —
Rope
. The lines are ropes.
Step 2.
Rope
— is used in —
Pulley
. A rope runs over the pulley.
Step 3.
Pulley
— is part of —
Elevator
. The rope runs over a pulley.
Open Evothings