C-PS/8 FOCAL, 1971
 1.01 C     FROM PLOTER IN 	FOCAL PROGRAMMING MANUAL	
 1.02 C     PDP-15 SYSTEMS  COPYRIGHT 1970  MODIFIED BY JOHN HUISMAN
 1.03 C     OMSI SOFTWARE DEVELOPMENT GROUP
 1.04 C     LAST CHANGE: 8/9/71
 1.05 
 1.06 C     THIS PROGRAM WILL SIMULTANEOUSLY PLOT THE EUCLIDEAN
 1.07 C GRAPHS OF ANY THREE FUNCTIONS.  REMEMBER THAT YOU ARE IN
 1.08 C FOCAL, SO ANY FUNCTIONS YOU USE LIKE SINE MUST APPEAR AS
 1.09 C 	FSIN	.  THE EQUATIONS ARE IN GROUP 10 WHERE THEY MAY BE
 1.10 C MODIFIED.  TO PLOT LESS THAN ALL THREE EQUATIONS, JUST
 1.11 C SET ONE OF THE EQUATIONS TO A CONSTANT WHICH WILL BE OFF
 1.12 C YOUR SCALE.
 1.13 C ** Y SCALING FACTOR IS THE NUMBER OF Y-UNITS EACH DOT REPRESENTS
 1.14 C ** UPPER AND LOWER LIMITS ARE THE X-VALUE	S LIMITS
 1.15 C ** INCREMENT REFERS TO THE STEP BY WHICH THE X=VALUES ARE TAKEN
 1.16 C ** THE PLOT ARRANGES YOUR PARAMETERS TO GO THROUGH X=0
 1.17 
 1.30 E
 1.33 A "HAVE YOU INPUT THE EQUATIONS YET
 ",AN
 1.36 I (AN-0NO) 1.5,1.4,1.5
 1.40 T !!"HERE ARE THE EQUATIONS.  TYPE 	G	 TO RESTART."!!;W 10
 1.45 Q
 1.50 A "LOWER LIMIT ",LL,!"UPPER LIMIT ",UL,!"INCREMENT ",IN,!
 1.60 S Y(1)=0;S Y(2)=0;S Y(3)=0
 1.70 A "DO YOU WANT A TABLE OF VALUES
 ",AN
 1.80 I (AN-0YES) 4.05,1.9,4.05
 1.90 F X=LL,IN,UL;D 10;D 2
 2.10 I (Y(2)-Y(1)) 2.14,2.12,2.14
 2.12 T "1 & 2 INTERSECT AT:"!
 2.14 I (Y(3)-Y(2)) 2.2,2.16,2.2
 2.16 T "2 & 3 INTERSECT AT:"!
 2.20 I (Y(1)-Y(3)) 2.3,2.25,2.3
 2.25 T "1 & 3 INTERSECT AT:"!
 2.30 T "X=",X,"    Y1=",Y(1),"    Y2=",Y(2),"    Y3=",Y(3),!
 3.10 A "DO YOU WANT A PLOT
 ",AN
 3.20 I (AN-0YES) 9.1,4.05,9.1
 4.05 A !"Y SCALING FACTOR: ",YS,!!
 4.07 F A=1,66;S P(A)=160
 4.10 F X=IN*FITR(LL/IN),IN,IN*FITR(UL/IN);D 5
 4.20 Q
 5.05 
 5.15 S P(33)=174
 5.20 I (-FABS(X)) 5.3;S P(1)=217;F A=2,65;S P(A)=174
 5.25 S P(66)=217
 5.30 D 10;F A=1,3;S Y(A)=Y(A)/YS
 5.40 I (33-FABS(Y(1))) 5.5;S P(Y(1)+33)=163
 5.50 I (33-FABS(Y(2)))5.6;S P(Y(2)+33)=170
 5.60 I (33-FABS(Y(3)))5.7;S P(Y(3)+33)=171
 5.70 D 6;R
 6.02 S M=67
 6.04 S M=M-1;I (P(M)-160) 6.1,6.04,6.1
 6.10 F A=1,M;S AN=FOUT(P(A));S P(A)=160
 6.20 T !
 9.10 Q
10.10 S Y(1)=X
10.20 S Y(2)=X*X
10.30 S Y(3)=200