unsquare

unsquare is a tool to help you explore and reason about four-sided shapes (quadrilaterals). I use it to help me figure out how to arrange a shape that's "not quite square" into a piece of material with a straight edge.

1. Measure and input each of the side lengths and the two diagonals into the Measured column.

   AB

   is the length from point A to B,

   BC

   is the length from point B to point C, and so on.

   AC

   and

   BD

   are the lengths of the diagonals.
2. After entering all of the lengths, unsquare will estimate the "true" values of the measurements and enter them in the Estimate column. The estimates are made such that all measured lengths in combination form a valid quadrilateral.
3. Any differences between the initial measurements and the estimates are shown in the Error column.
4. The ΔX and ΔY columns show the projected lengths of the estimates along the X and Y axes.
5. Hover over the side lengths in the resulting diagram to see their values.

1. Units changes between Metric (unitless decimal) and Imperial (feet and inches). An example of the format for Imperial measurements is:

   4' 3 1/2"

2. Root sets which point (A, B, C, or D) will sit on the "straight edge".
3. Horizontal sets whether the "straight edge" will be shown left-to-right or top-to-bottom.
4. Flip changes the ordering of points between clockwise and counter-clockwise.
5. Save allows you to enter a name to save a quadrilateral for later.
6. Load allows you to load a previously-saved quadrilateral.
7. Randomize will generate a random quadrilateral.
8. Clear will clear all values so you can start from scratch.