'POLAR FUNCTIONS
SCREEN 12:CLS
XC=320:YC=240
R1=100
R2=60
PI=4*ATN(1)
'DEF FUNCTION
F$(1)="R1*SIN(6*F)+R2"
DEF FNA(F)=R1*SIN(6*F)+R2
F$(2)="2*R1*SIN(6*F)*SIN(5*F)"
DEF FNB(F)=2*R1*SIN(6*F)*SIN(5*F)
F$(3)="R1"
DEF FNC(F)=R1
F$(4)="R1+10*SIN(15*F)"
DEF FND(F)=R1+10*SIN(15*F)
NM=4
FOR I=1 TO NM
?I;". FNR(F)=";F$(I)
NEXT I
?
INPUT"SELECT FUNCTION";NF
CLS
?"FN=";F$(NF)

DEF FNN(N)=1-SGN(ABS(SGN(N-NF)))
DEF FNR(F)=FNN(1)*FNA(F)+FNN(2)*FNB(F)+FNN(3)*FNC(F)+FNN(4)*FND(F)
'==================================
DF=PI/(4*360)
FOR F=0 TO 2*PI STEP DF
 X=XC+FNR(F)*COS(F)
 Y=YC+FNR(F)*SIN(F)
 PSET(X,Y),10
NEXT F
'==================================
LOCATE 22,1:?"HIT <ESC> - TO QUIT"
WATA:
 IF INKEY$=CHR$(27) THEN STOP ELSE WATA