In 1994, Clay Halliwell created FlickerTerm 80, an ANSI/VT100 terminal emulator program, which uses 40×24 text mode, combined with two character sets with an identical 4×8 font—one with the pixels on the left half of the 8×8 grid, the other on the right. By alternating where in memory ANTIC looks for graphics, and which font to display, an 80×24 character screen can be displayed. It uses less memory (about 2 KB) and can be more quickly manipulated, compared to rendering 80×24 characters using a 320×192 bitmap mode (which would require about 8 KB). The disadvantage of this mode is the 60Hz flicker on all displayed charactes (50Hz on PAL systems). As such, it was most legible on monitors with high-persistence phosphors.
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