JavaScript Taskbook Level 8.3

Let's say there are checkboxes, checked and unchecked. When you click a button, make all the checkboxes change their state.

The following array is given:

javascriptlet arr = [1, 2, 3, 4, 5, 6];

The number is also given:

javascriptlet num = 3;

Add as many empty strings to the given array as necessary so that the length of the array becomes equal to the square of the number from the variable.

Display the following pyramid on the screen: