event flow diagram of fig8 the gesture recognition routines in fig6 are the greater part of the dragprocessor class as represented in both the class diagram and the event flow diagram of fig7 and fig8 in particular fig7 shows the interconnection of a drag processor 701 event processor 703 drawing canvas 705 view manager 707 and chemistry model classes 706 as shown in fig7 the drag processor 701 sends corners detected to the event processor 703 and receives mouse movement data from the event processor 703 the event processor 703 receives miscellaneous data from the chemistry model classes 706 and user input events from the drawing canvas 705 the event processor 703 sends commands to the view manager 707 in addition fig7 shows the drawing canvas 705 sends point gesture events to the view manager 707 the view manager 707 send sends set model data to match the user 39 s drawing to the chemistry model classes 706 the chemistry model classes 706 sends current model data for displaying the reaction to the view manager 707 an event flow diagram for the present invention is shown in fig8 the block of events enclosed by bracket a of fig8 are repeated as many times as there are mousemove events between the mousedown and mouseup the block of events enclosed by bracket.