Lewis Carroll's Logic Game . With the applet below you drag counters to one of the eligible positions on the trilateral diagram. This is where you formalize your premises. The conclusion is read off from the bilateral diagram on the right.
Some actions have an immediate effect.
For example, a single red counter in the inner North-West square which corresponds to Some xym exist is immediately interpreted as Some xy exist . No interpretation for the trilateral diagram is provided in this case. The same happens in other cases too. There are two reasons for such an implementation. Configurations of the trilateral diagram meaningful in this context are collected in a special table .