Texas Instruments TI-83 Manual Book page 230

specifies one of eight shading resolutions.
patres
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patres 1
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patres 2
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patres 3
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patres 4
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patres 5
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patres 6
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patres 7
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patres 8
Shade( lowerfunc,upperfunc[,Xleft,Xright,pattern,patres] )
TI-83 Plus Draw Instructions
shades every pixel (default)
shades every second pixel
shades every third pixel
shades every fourth pixel
shades every fifth pixel
shades every sixth pixel
shades every seventh pixel
shades every eighth pixel
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