Contour lines refer to the closed curves formed by adjacent points of equal height on a topographic map.

A closed curve is formed by connecting points with the same elevation on the ground, projecting them vertically onto a horizontal plane, and proportionally scaling them on a drawing to obtain contour lines.

This model combines planar contour lines with three-dimensional mountain ranges, which is more conducive to students' understanding of the principles of contour lines and is a very good teaching tool.

This model is taken from Mount Taishan Mountain in China. It is a very grand mountain. 

I hope you like it.