Given 2 points how do I draw a line at a right angle to the line formed by the two points?

Idealy I want to supply a sequence of points and have a line drawn at a right angle at every point (starting at the second point).

The direction of each line would alternate, so if I happened to draw a curve cosisting of 6 points, a line of a given lenth would be drawn for each point starting with the second point, i.e 5 additional lines on alternating sides of the curve, a bit like a caterpillar with alternating legs.

(I understand that the lines won't be entirely at right angles to the curve but rather at right angle to the line formed by any two points on the curve).