Konstrukt 2

Konstrukt 2

Konstrukt is an SVG + ECMAScript application for compass and straightedge construction. It's not too unintuitive to use, once you know what the controls are:

to draw a straight line through two marked points
press the v key and click on the two points
to draw a circle centered at one marked point through another
press the c key and click on the two points (the first of which is the center)
to delete a marked point and all edges through it
press the x key and click on the point (tip: you might create extra lines and circles for the purposes of deleting at an intersection)
to move the viewpoint
click on empty space to center the view on that position
to zoom in
press the PgUp key
to zoom out
press the PgDn key

New in Konstrukt version 2 are some more attractive drawing tools that are locked to the construction points, useful perhaps for mathematical diagrams like the above 3 octahedra around a line in a 24-cell:

to draw a line segment between two marked points
press the s key and click on the two end points
to change the line segment thickness
press the - key or the + key
to draw a filled polygon
press the f key and click on as many points as you like, then press the z key
to change the fill colour for future polygons
press the [ key or the ] key