You can achieve this to a limited extent by using the Rotation Angle feature when you draw a Shape on the page.
However, Bubble doesn’t handle creating objects like this very well because the “overflow” isn’t hidden. (ie. you’ve only tilted a rectangle. So it’s not quite a triangle. You could do some fancy hiding in groups, but that’s unnecessary effort and isn’t well suited for responsiveness).
I recommend drawing the object in a tool like Pixlr, saving it as a transparent PNG and then dropping the image on the page.