Interpolation - it's a function f(P1, P2, t) that gives you a point between 2 points for given t ∈ <0, 1> ( imagine you walk on path between point A and point B and you stop after you finished exactly 34,2353% of the whole road. To know what is your current point on path, you calculate interpolation f(A, B, 0.342353) )

Polynomial interpolation - it's just a interpolation of two interpolations which are interpolations of two interpolations and on and on.... So quadratic interpolation is just a interpolation of two interpolations. (it's a situation when we have 3 points - cubic interpolation it's when we have 4 points)

Quadratic Bezier curve - it's a curve drawn using interpolation of two interpolations (A -> B, A -> C)

Cubic Bezier curve - it's a curve drawn using interpolation of two interpolations of two inteprolations 1st interpolations: A->B, B->C, C->D 2nd inteprolations: (A->B)->(B->C), (B->C)->(C->D) 3rd (final) interpolation: ((A->B)->(B->C))->((B->C)->(C->D))

cubicTo(x1,x2,x3) - it's just drawing a cubic Bezier curve. You might ask, where is the fourth point? The fourth point is where you currently are on Path, it's a starting point.

Draws line towards opposite corner of square ( this line is just a diagonal of square with size of (height - cornerLength / 2) )

Starts in bottom-left ( in Graphics 2D drawing starts from top-left, that's why coordinates are (0, height) )