I've looked in Pixelmator's help, searched the internet, Googled everything I can think of, and tried experimenting on my own, but for the life of me I cannot figure out how to change the tip shape of any given tool from a circle to a square. Started out I was trying to erase something that had very straight edges and couldn't use the magic eraser because it was too close to the colour of the image I wanted to keep. Then I realized I was unable to change the shape of any of the tools.
So where is the square tip? I can find every other way to make a stroke or brush tip EXCEPT for this!?! It seems to be a very basic thing for someone to want to do so there's got to be a way to change it, seeing as Pixelmator is so advanced, right? Can someone please help???