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This problem involves circuits which feed back into themselves: The output of a gate can be traced through the circuit back into the input of the same gate! This can lead to all sorts of interesting behaviour, which will be explored in this problem. Please note that the gates here are not interactive: they are thought experiments .
What will happen when you switch on these circuits?
What will happen if you change the gates to different types?
The following two circuits have the same gates. Look carefully at the wires which are switched on. What do you notice? What do you think will happen when the switches are flicked on and then flicked off?
Can you create your own feedback circuits? Investigate their properties.
Click here for a poster of this problem.
This is about a fiendishly difficult jigsaw and how to solve it using a computer program.
This follows up the 'magic Squares for Special Occasions' article which tells you you to create a 4by4 magicsquare with a special date on the top line using no negative numbers and no repeats.