3D Modeling - Learn OpenGL ES: For Mobile Game and Graphics Development - page 143

Note If you accidentally deleted the cube mesh from the grid, you
can add it back again. Snap (crosshair) cursor to the center ( Figure
4-18 ) by pressing Shift S , and add the cube mesh by selecting it from
Add menu, as shown in Figure 4-19 .
Figure 4-18 . Snap cursor to center
Figure 4-19 . Adding a mesh
Creating an Equilateral Triangle