Idea of Hans de Rijk, published in the Bulletin of "De Zonnewijzerkring" nr. XI, 1982.
Take a pole style and an equatorial ring with hour points, and orient them as necessary for your location.
The figure above shows an example on a horizontal plane, but planes of any orientation may be used.
Hour lines on the plane are not necessary.
When the sun shines, the style and ring cast their shadows on the plane, and where the shadow of the pole style intersects the shadow of the equatorial ring, the time is read.
But, you will object, there are no numbers there.
That is correct, and therefore we introduce them, but on the real hour points.
By keeping a finger or a pencil at the hour points, the corresponding shadows are simply found, and we know which hour goes with which shadow point.
If the shadow falls too far away, you can catch it on a sheet of paper behind the ring: any plane may be used for this sundial.
Sometimes the readout is ambiguous. To resolve it, you should have some idea of which part of the day you are in.
This example shows just one of many possible Shadow Dials. The others we gladly leave to your own imagination.
Fer de Vries
English translation: RH