Elsewhere In the AutoCAD forum the enquirer allowed that to avoid the issues arising from his choice of tilesize and spacing ensuing from 3mm grout between tiles that the larger tile could be increased to size 603 wide by 600 high therby adsorbing the 3mm grout joint. Any change in appearance of the pattern by doing this would be imperceptible in practice.
Anyway here's the grouted pattern with 3mm grout and a widened tile:
Adopting a slightly larger tile that won't markedly affect the overall appearance is a very sensible and pragmatic solution.
;-------------------------------------------------------------------------------
; Written by HatchKitCS
; HatchKitCS (c)1990-2017 Cadro Pty Ltd
; www.hatchkit.com.au
;-------------------------------------------------------------------------------
;%VERSION=3.0
;%UNITS=MM
*tiles300and603
;%TYPE=MODEL
-90,1.5,-1.5,603,303,600,-1209
0,1.5,-601.5,303,-603,603,-306
0,1.5,-1.5,303,-603,603,-306
180,-1.5,-1.5,-303,603,300,-609
-90,-301.5,-1.5,603,303,600,-1209
-90,-1.5,-1.5,603,303,600,-1209
0,-301.5,-601.5,303,-603,300,-609
-90,604.5,-1.5,603,303,600,-1209
This is also a skewed pattern that does not rely on the rectangular arrangement.
imposed by all other hatch pattern utilities.
This pattern if defined with a rectangular arrangement requires a larger template consisting of 16 elements.