100 CLS:KEY OFF:LOCATE 10,35:PRINT"More Moire:":LOCATE 11,24:PRINT"A program for pattern generation.":LOCATE 12,14:PRINT"Do you want background information and instructions?"
110 A$=INKEY$:IF A$="" THEN 110
120 IF A$ <>"n" AND A$ <> "N" AND A$<>"y" AND A$<>"Y" THEN 110
130 IF A$ ="n" OR A$ = "N" THEN 160
140 GOSUB 1210
150 '********* INPUT OF PARAMETERS FOR PATTERN GENERATION *********
160 CLS:INPUT"Enter a number from 1 to 39: ";O1:INPUT"Enter a number from 1 to 30: ";O2
170 PRINT:PRINT"Select one:":PRINT" 1 - X*X and Y*Y":PRINT" 2 - X*Y and Y*Y":PRINT" 3 - X*Y and Y*X":PRINT" 4 - X*X and Y*X"
180 A$=INKEY$:IF A$="" THEN 180
190 IF A$ <> "1" AND A$ <> "2" AND A$<>"3" AND A$<>"4" THEN 180
200 PRINT"You have selected ";A$;"."
210 PRINT:PRINT"Select one:":PRINT" 1 - O1 and O1":PRINT" 2 - O1 and O2"