Make canvas paint brush square shaped?

Hello everyone! Ive been wondering if there's an easy way to get the paint brush to be square shaped no matter what device the user is using. Ive tried my app in an emulator and the paint brush was a perfect square, but when I switch to actually using the app on a mobile device, the paint brush looks like a dot with a bigger ring around it.

Id be super happy if anyone could help me and thanks in advance for every reply!!

which block are you using to draw?

How thick is your line width or circle radius, compared to Canvas1.Width and .Height?

Different devices might have different sizes in pixels, but your dots might not reflect that.