lens
pencil
lawn chairs
hands on a clock
arrowhead...
Some examples are: circle, square, rectangle, right angle triangle, equilateral triangle
Non-examples of similar shapes include a rectangle and a triangle, as they have different numbers of sides and angles. Another example is a circle and an oval; while both are curved shapes, their proportions and dimensions differ significantly. Additionally, a square and a rhombus, although both have four sides, do not have the same angle measures, making them not similar.
reflex angle
leaf
Oh, dude, a reflex angle is greater than 180 degrees, so if you draw one arm of the angle straight, the other arm would have to be pointing backwards, which is like, not really a thing in normal geometry. So, technically, no, you can't have a straight angle and a reflex angle sharing an arm. But hey, if you're feeling creative, go for it, who am I to stop you?
There's no such thing as the diagonal of an angle anyway. If there's an irregular polygon that has some reflex angles in it, there's no reason the polygon can't have diagonals that terminate in them.
Some examples are a square, rectangle, that is all I know so far
buildings, desk, door
Some two-dimensional shapes: square triangle rectangle diamond circle trapezoid
Some examples of 3D shapes with angles include cubes, pyramids, and rectangular prisms.
A ramp, angle of mountain
A kite, if the topmost angle is right and none of the others are.