3. Gate

Using the Tinkercad tool, create a gate.
Use objects: 2 cylinders, 2 cubes, and 1 half cylinder.

Place the cylinders on the cubes, which will be spaced the length of a half-arc apart. Then, on top of the cylinders, place the half-arc.

Cylinder:

Diameter: 15
Height: 50

Cube:

a = 15

Half Cylinder:

Length: 80
Width: 15
Height: 15