Some activities ask you to make a construction yourself using a set of buttons. Here is a simple guide to what each button does. Move a point by clicking and dragging. Construct a perpendicular to a line by first selecting a point and a line (but not a segment of a line!) Add a point, by moving to the position you want a point and clicking (or by pressing then dragging then releasing) Construct the midpoint by dragging between two points Use the compass to draw a circle by clicking first where the centre is, then where the circumference is and last where you want this circle positioned. Construct a parallel to a line by first selecting a point and a line (but not a segment of a line!) Construct a line through two points by clicking then dragging then clicking. A locus is defined by three objects: the mover; the road; the tracer, which must be selected in this order. The first mouse-click selects the "mirror". The following clicks select the elements that should be reflected. Undo your last step - and the step before that, and so on... Give a hint Clear everything and start again.