Shikaku rules

Rules

Divide the grid into rectangles such that each rectangle contains exactly one number and such that this number equals the area (i.e. the number of cells) of the rectangle.

Example

Here is a grid of Shikaku and its solution.

Shikaku example grid
Shikaku example grid solution

Solve the example online here.

History of Shikaku

According to the WPC unofficial wiki, Shikaku is a puzzle first published in 1989 in Nikoli. It was invented by Yoshinao Anpuku.