I have evaluated the border command and have come up with a short demo to show off just a fraction of what is possible with the BORDER command.
100 REM border sheninigans
110 SCREEN 4:CLS:BORDER 0,0
120 PRINT "BORDER SHENANIGANS!"
130 PRINT "BORDER uv,y[,x,w]"
140 PRINT "uv component color 0-255"
150 PRINT "y component color 0-153"
160 PRINT "x 0-183"
170 FOR z=10 TO 160 STEP 50
180 FOR x=0 TO 60
190 GOSUB &uvy
200 BORDER uv,y
210 WAIT z
220 GPRINT 0,150,z
230 NEXT x
240 NEXT z
250 REM next one
255 SCREEN 4:CLS:BORDER 0,0
256 "press <CRTL-C> to exit"
258 DO
261 z=INT(183RND(0))
265 GOSUB &uvy
270 BORDER uv,y,z,1
275 WAIT 1
285 LOOP
287 END
290 &uvy:
310 uv=INT(255RND(0))
320 y=INT(153*RND(0))
330 RETURN