02-05-2017, 01:47 AM
It is mentioned very briefly in the ZX Basic manual, <!-- m --><a class="postlink" href="http://www.worldofspectrum.org/ZXBasicManual/zxmanchap13.html">http://www.worldofspectrum.org/ZXBasicM ... hap13.html</a><!-- m -->
But turns out to be far more useful. See this program that creates the +2 test screen :
10 FOR l=0 TO 21 : FOR i=7 to 0 STEP -1 : PRINT INK (l and l<8); PAPER i;("19" AND l<8); (" " AND l>= 8 ) ; BRIGHT 1; ("86" AND l<8); (" " AND l>=8);: NEXT i : NEXT l
You can see a live version of it here :
Run demo
But turns out to be far more useful. See this program that creates the +2 test screen :
10 FOR l=0 TO 21 : FOR i=7 to 0 STEP -1 : PRINT INK (l and l<8); PAPER i;("19" AND l<8); (" " AND l>= 8 ) ; BRIGHT 1; ("86" AND l<8); (" " AND l>=8);: NEXT i : NEXT l
You can see a live version of it here :
Run demo