\\ Sample script to turn BOYAN into an Etch-a-Sketch!

\\ This script is fairly advanced, demonstrating the following techniques:
\\ 1. Cursor movement and screen control
\\ 2. Saving the beeps & bells toggle for later restoring
\\ 3. Reading and testing user input
\\ 4. Separating a script into blocks: START, DRAW, and *WRAPUP

|START
\GL-                      \\ switch into 25-line mode (if now in 43-line mode)
\KS                       \\ keep (store) the current screen contents
\ST[ Welcome to BOYAN Etch-A-Sketch! ]   \\ status message
\SV3[%BB]                 \\ save current beeps&bells value in variable 3
\BB-                      \\ turn beeps&bells off
\KO[60]                   \\ set keyboard timeout to 60 seconds
\GX[40]  \GY[12]          \\ start in the middle of the screen (40,12)
\DM%XP,%YP[±]             \\ display a shaded block at cursor position

|DRAW
\DM1,24[<I>=up ³ <J>=left ³ <K>=right ³ <M>=down ³ <Esc>=exit       ]
\DM24[³ X-pos=%XP ³ Y-pos=%YP ] \\ display status on line 1
\KV1_[Your Etch-a-sketch command? ]          \\ get char input from keybd
\DM%XP,%YP[ ]             \\ display a space at current x,y cursor posn
\IV1+I[\RY[-1]]           \\ move up if input="I"
\IV1+J[\RX[-1]]           \\ move left if input="J"
\IV1+K[\RX[1]]            \\ move right if input="K"
\IV1+M[\RY[1]]            \\ move down if input="M"
\DM%XP,%YP[±]             \\ display a shaded block at cursor position
\GB[DRAW]                 \\ loop back for more input!

|*WRAPUP
\RS                       \\ restore previous screen contents
\IE+%V3,ON[\BB+]          \\ turn beeps&bells back on if they were on before
\ST[Etch-a-sketch completed!]  \\ Status message