To explore how ReasonLines works, first make sure that AutoSolve and Use Numbers buttons in the top right corner are not selected. Now drag a schematic card (a set of arrows) up onto the rectangle containing "Drop card here" and whose corners are A, A, B, and B. This will represent a premise whose terms are indicated by these letters in the circles. When the card is in place, click or tap it to see what four "sentence forms" the arrows represent. You may want to see if you can relate the individual arrows to the respective sentence forms. Now activate the AutoSolve feature and watch the same schematic appear in the Conclusion box (bottom right). Then drag any schematic up into the next rectangle whose corners have now become B, B, C, and C; at this point the Conclusion box will either read "No conclusion" or it will display a schematic between the corners that have now become A, A, C, and C. If "No conclusion" appears, continue to replace the second schematics with some other until a conclusion schematic does appear. Click or tap the conclusion to see what sentence forms its arrows represent. Note how each green arrow of the conclusion schematic directly connects A or A with C or C while these are the same terms that are connected by a "green arrow path" that runs through B or B on the two premise schematics. (Sometimes there are two single-ended, green arrows pointing opposite directions in the conclusion; for the other times there is only one green arrow but, being double-ended, it points both directions.)
The difference between the conclusion schematic and the set of premise schematics illustrates one important feature of logic, viz., that drawing a conclusion from more than one premise is always a matter of eliminating the "middle terms" (here B and B). But this cannot always be done since more often than not no conclusion at all follows; and when a conclusion does follow, it is properly represented by only one of the eight schematics.
Additional premise schematics can be added to create sorites of any length (although they run off-screen after a few) and the AutoSolve feature can be turned off to allow users to propose their own conclusions. The Reset button on the top-left will clear all entries and display the opening screen.
The "Use Numbers" feature allows the schematics to function for the expanded, numerical logic for which they were initially devised. To change a number, one can touch/hold the numeral on any card that has been manually entered until the number pad appears. This numerical expansion of the logic will be presented in some detail in Part Two of the Tutorial below, but first the traditional logic will be developed and fitted to the schematics.