beautiful-racket/beautiful-racket-demo/basic-demo-nth/3dplot.bas

#lang basic-demo-nth

1 PRINT TAB(32);"3D PLOT"
2 PRINT TAB(20);"RACKET COMPUTING · HOLLYWOOD"
3 PRINT:PRINT:PRINT
5 DEF FNA(Z)=30*EXP(-Z*Z/100)
100 PRINT
110 FOR X=-30 TO 30 STEP 1.5
120 L=0
130 Y1=5*INT(SQR(900-X*X)/5)
140 FOR Y=Y1 TO -Y1 STEP -5
150 Z=INT(25+FNA(SQR(X*X+Y*Y))-.7*Y)
160 IF Z<=L THEN 190
170 L=Z
180 PRINT TAB(Z);"*";
190 NEXT Y
200 PRINT
210 NEXT X
300 END