JS nesting loops staircase

Question

Trying to get a pattern on the canvas with squares in js using loops that looks like this

■

■ ■

■ ■ ■

I currently only have the first loop of squares and am unsure of how to nest the second loop to get this effect. Here is my js

var canvas = document.getElementById("myCanvas");
var ctx = canvas.getContext('2d');


ctx.fillStyle = "rgba(255, 255, 255, 255)";
for(var i = 0; i < 10; i++) {
    ctx.fillRect(i*25, i*25, 20, 20);
}

Answer 1

You need an inner loop, to draw all the n squares in the nth line:

for(var i = 0; i < 10; i++) {
    for(var j = 0; j <= i; j++) {
        ctx.fillRect(j*25, i*25, 20, 20);
    }
}