eidophor

例句：

1. 1. The eidophor was used to measure the angles of the walls.
   视差仪被用来测量墙壁的角度。
2. 2. The parallax effect is caused by the Earth's rotation.
   视差效应是由地球的旋转引起的。
3. 3.The parallelogram is a shape with four equal sides and right angles at each corner.
   平行四边形是一种有四个相等边的多边形，每个角都是直角。