Building Formulae
Goal
The challenge formula is displayed inside the small black
panel. The goal is to build the same formula inside
the big black panel. Initially the big black panel contains only
the atomic elements of the challenge formula.
In order to compose them and get the whole formula, six actions
are proposed:
 Copy: Clicking on a formula copies it
 Dissolve: Clicking on a formula removes
its top operator. If the formula is atomic, it cancels it.
 And: Clicking on a first formula f1 and
dragging towards another
formula f2
creates the formula f1 ∧ f2.
 Or: Clicking on a first formula f1 and
dragging towards another formula f2
creates the formula f1 ∨ f2.
 Imp: Clicking on a first formula f1 and
dragging towards another formula f2
creates the formula f1 > f2.
 Neg Clicking on a formula f adds
a negation on top: ¬f.
Hints:
 A new challenge is generating by pressing on the button Next.

Passing over the challenge formula with the mouse highlights its structure.

Actions can be enabled by selecting the corresponding checkbox,
using the vertical arrows. or using the mouse wheel.
This applet has been tested with Java 1.4.2 (Sun).
Check your version of java
Laurent Théry