First click anywhere on the center board. A random pattern of ladders and rungs will appear connecting the left set of eight phones with the right set of eight phones.

One of the phones on the left border will turn red and ring. Your task is to click the one phone on the right border which is connected to it.
Here is how you find the correct phone on the right:
Starting with the red phone at the left border, go right along the straight until the next intersection with a vertical rung. Follow this rung up or down to the next horizontal bar, then go to the right again to the next intersection and so on.

If you pick up the wrong phone you lose.
If you pick up the right phone, the button ot the bottom will show the text 'NEXT'. Click this button and the next phone will ring.
You can also click the 'SOLVE' button to let the system find the right phone to pick up.
You win when you have found the connections for all phones.

Variant 2 has more complicated connections.
Variants 3 and 4 have ten phones on each side.

 
Background design: Fractal Z010103r by Karl Scherer.

The 'ladders and rungs' system used here is a classic method to create one-to-one associations betweens sets of equal size. It is sometimes used by students in Japan to randomly associate tasks to persons as an alternative to drawing straws.

More freeware and real puzzles and games at my homepage: karl.kiwi.gen.nz .