This geometrical shape isn’t needed frequently, but sometimes, it proves to be very useful.
To draw a spiral, click and drag with the mouse on the canvas. When the left mouse button is released, the spiral will be finished. You will notice two diamond-shaped handles on the spiral.
These handles change the length of the spiral. You can try this out right on the canvas: Just grab one of the handles and drag it along the spiral’s turns to get the desired number of turns and to make the spiral larger or smaller.
If you hold down Ctrl while dragging the handles, the spiral will get longer (or shorter) in 15° steps.
When you combine pressing Alt with pulling the inner handle upwards or downwards, it will change the divergence (tightness) / convergence (looseness) of the spiral, without changing its overall size. Dragging upwards makes the turns move toward the outside of the spiral. Dragging downwards will make them move closer to its center.
The easiest way to change the number of turns of a spiral quickly by a large amount is to enter the desired number into the field labelled Turns in the tool controls bar. This will not change the spiral’s diameter.
If you ever feel lost when working with the spiral tool, you can use the rightmost icon in the tool controls bar to remove all changes and to reset the spiral to its initial shape.