Ladder rungs and joystick: what they have in common

1. Step 1. Ladder rungs — is part of — Ladder. Rungs for the feet.
2. Step 2. Ladder — uses — Inclined plane. Climbing to a height.
3. Step 3. Inclined plane — is used in — Egyptian pyramid. According to a common hypothesis, the blocks were raised on ramps.
4. Step 4. Egyptian pyramid — uses — Lever. Levers were used to move the blocks.
5. Step 5. Lever — is used in — Joystick. A lever.

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