I am remaking the ITPs so that they will work on all modern browsers and tablets. They will remain freely available to all without the need for a subscription.
This ITP allows you to create a number of connected vertices on a grid. The grid size can be changed, and the grids hidden and revealed. As each vertex is created it is labelled and joined to the previous one. To close a shape select a vertex at any point and drag it onto the required point to create a closed shape. Once a shape has been created, its vertices can be dragged to new positions to create new shapes. Lengths of sides can be measured using a ruler.
The angles created at vertices can be measured using the protractor and their values can be displayed or hidden. For reflex interior angles the value of the exterior angle is shown. You can use the ITP to demonstrate and explore properties of shapes, such as the internal angles of different pentagons and the properties of opposite sides of various parallelograms in different orientations.