Listing 3 Assuming you have a WORKING copy of Listing 2, named as, perhaps, APOLLO11.BAS, "Copy As" APOLLOOP.BAS to provide the basis for this separate program. Listing2, line 15 is - "apogee = 549200". Replace this with colour = 0 'ie. 4 lines FOR apogee = 618000 TO 440000 STEP -60000 IF apogee = 498000 THEN apogee = 547220 'note 547220 colour = colour + 1 AND, change the final 2 lines (94 & 95, BEFORE SUB Init) to LOOP UNTIL finish = 1 'ie. 2 extra lines DO:LOOP WHILE INKEY$ = "": finish= 0 'reset for next FOR NEXT 'end of FOR apogee = ... DO: LOOP WHILE INKEY$ = "" Now, eliminate line 20, "IF colour=1 THEN" AND next 8 lines including "END IF". (We are not drawing these) At this location, insert following WINDOW(-10000,10000)-(390000,-290000) 'ie.earth/moon arena FOR yc=-200000 TO -80000 STEP 40000 'energy scale - units LINE (0, yc)-(9000, yc), 4: NEXT FOR yc=-200000 TO -80000 STEP 4000 'energy scale - tenths LINE (0, yc)-(4000, yc), 4: NEXT : COLOR 4 FOR n = -2 TO 1: LOCATE 14 - n * 4, 5: PRINT n: NEXT LOCATE 19, 26: COLOR 15 'table heading PRINT "Apogee mindm hr min Erq Fuel" Immediately before "SELECT CASE", change "PSET (x, y), 15" to "PSET (x, y), colour" 'colour coding 4 routes And, delete previous 3 lines, ie tp = ...... & next 2 lines Now, in CASE 2, eliminate line 75, "IF colour = 1 THEN" and next 6 lines including "END IF" (not drawing these) (Note. Originally intended to show Sectors 1 - 3 on screen) before 1st loop only(colour=1) but now eliminating this and will only draw on big WINDOW (covering earth to moon). So you may also delete SUBs Init and Tidyup - Press F2, highlight SUB with cursor then click on "delete" Replace CASE 3 with simpler version CASE 3: 'COASTING AFTER BURN IF t MOD 60 = 0 THEN 'each minute IF tm = 190 THEN 'end Sector 3 at 190 min Sector = 4: ti = 5: mindm = 400000: flagdm = 0: END IF END IF And add CASE 4 as follows CASE 4: 'Sector 4, Version 1. MULTIPLE TRIPS AROUND MOON IF mindm > dm THEN mindm = dm + 1 'keep adjusting minimum IF flagdm = 0 AND dm > mindm THEN 'when minimum passed LOCATE 19 + colour, 25: COLOR colour PRINT apogee;mindm; hr; min; Erq; CINT(m-61199):flagdm=1 DO: LOOP WHILE INKEY$ = "" 'print minimum, stop looking END IF IF t MOD 60 = 0 THEN 'every minute IF min = 0 THEN 'every hour, mark time scale IF hr<70 OR hr>110 THEN LINE(x,y)-STEP(0, 3000), colour PSET (tm * 20, (E - 3) * 40000), colour 'plot energy IF hr MOD 10 = 0 THEN 'every 10 hours LINE (x, y)-STEP(0, 8000), colour 'mark time scale IF colour=2 AND y< -10000 THEN 'print hour (2nd route) LOCATE -y / 10000, x / 5000: COLOR colour: PRINT hr END IF 'end IF colour END IF '10 hour END IF 'hour END IF 'minute IF x > xm THEN CIRCLE (xm, ym), 1000, colour 'draw moon IF y > ye THEN Sector = 5 'CASE ELSE will now finish it.