In operation, Print1456.class provides 10 possible entry points. At the moment of start up there is one entry point available. 1: is for start up. After start up, at any time either 1 entry point is available or 8 entry points are available, depending upon whether the 1456 applet landscape Print1456.class has been instructed, using the software interrupt mechanism, to use 1 entry point or to use 8 entry points. When there is one entry point, which is the default situation at start up, or after a 12? software interrupt. 41: is for the mouse being pressed. When there are eight entry points, achieved after a 11? software interrupt. The 11? could be in the 1: routine or the 41: routine as desired. Once the entry points are split in this way the 41: entry point is not available unless a 12? software interrupt is used. 70: is when y is less than 350. 71: is when y is 350 or greater and x is less than 100. 72: is when y is 350 or greater and x is 100 or greater and less than 200. 73: is when y is 350 or greater and x is 200 or greater and less than 300. 74: is when y is 350 or greater and x is 300 or greater and less than 400. 75: is when y is 350 or greater and x is 400 or greater and less than 500. 76: is when y is 350 or greater and x is 500 or greater and less than 600. 77: is when y is 350 or greater and x is 600 or greater and less than 700. Please know that a 21? software interrupt will turn on the colour toolbar, which aligns with these selected regions. A 22? software interrupt will replace the colour toolbar and anything drawn on it with a white background. Please know that the colour toolbar and the splitting of the entry points are independent of each other. It may well be that typical usage will be to use both together, yet the 1456 programmer may, if he or she so chooses, split the entry points and not use the colour toolbar, perhaps writing a text character within each area. Also, the colour toolbar is simply filled rectangles drawn on the display screen by the 1456 applet landscape. An identical display could be produced by drawing filled rectangles using 1456 object code. The 1456 programmer may, if he or she so chooses, produce his or her own active areas on the screen using eutodraw graphics commands and by using the values of the coordinates of the mouse button press with condition tests and conditional jump instructions just using entry points 1: and 41: if so desired. Another possibility is to use 11? at start up and to use the split entry points and also have other active areas identified using 1456 object code starting at the 70: entry label. Regardless of whether one entry point or entry points are being used, the position coordinates of the mouse at a mouse press are placed in integers 5 and 6, x and y respectively. The shift key being down at the mouse press causes a 1 to be placed in integer 7. The shift key being up at the mouse press causes a 0 to be placed in integer 7. The control key being down at the mouse press causes a 1 to be placed in integer 8. The control key being up at the mouse press causes a 0 to be placed in integer 8. The alt key being down at the mouse press causes a 1 to be placed in integer 9. The alt key being up at the mouse press causes a 0 to be placed in integer 9. There are various features provided in the software interrupt service routine. The command 1? will, for this particular 1456 applet landscape, place the string "The 1456 engine in action." into ms1456[19]. 11? will split the entry points. 12? will unsplit the entry points. 21? will turn on the colour toolbar. 22? will turn off the colour toolbar. The lettering that is drawn by eutodraw commands may have its size and style changed as follows. 1120? SansSerif PLAIN 12 point 1122? SansSerif ITALIC 12 point 1180? SansSerif PLAIN 18 point 1182? SansSerif ITALIC 18 point 1240? SansSerif PLAIN 24 point 1242? SansSerif ITALIC 24 point 1360? SansSerif PLAIN 36 point 1362? SansSerif ITALIC 36 point 1480? SansSerif PLAIN 48 point 1482? SansSerif ITALIC 48 point 1600? SansSerif PLAIN 60 point 1602? SansSerif ITALIC 60 point 1720? SansSerif PLAIN 72 point 1722? SansSerif ITALIC 72 point