I'm a beginner Can someone help me with this JavaScript problem?

write a program that draws a square 200 pixels by 200 pixels and that looks like this square with colours red (red value 255), green (green value 255), blue (blue value 255) and yellow (red value 255 and green value 255, blue value 0). You cannot use methods of graphics like fillRect or fill, or lineTo etc. You need to work with each pixel, changing its RGB

You need to add some functionality to your page: button "Switch" will be placing the similar square on canvas changing yellow colour to magenta.