The Rectangle Grid tool is similar to the Square Grid tool except that lets you create rigid grids where the Snapping Points are spaced out in rectangles (not necessarily squares). Some or even all of the lines of the grid may be missing depending on which construction option was used to create the grid, but the snapping points will be the same in each grid. Here are the possible “grids” you can create with Rectangle Grid tool:
Even though some of these grids contain only horizontal or vertical lines, there are invisible snapping points along those lines. To define the size of the grid cells, drag from your initial touch point and then tap the Mark Button
After the grid cell size is defined, continue dragging to create the grid itself. Here’s an example of Rectangle Grid creation: