На Swissmicro форуме добавили подпрограммы рисования вертикальных/горизонтальных линий и решетки с заливкой клеток. Результат программы CHESS:

00 { 681-Byte Prgm }
01▸LBL "HLIND"
02 "∫"
03 GTO 00
04▸LBL "HLINE"
05 "×"
06▸LBL 00
07 SIGN
08 X<0?
09 STO- ST Y
10 X<> ST L
11 44
12 XY?
51 GTO 03
52▸LBL 01
53 R↓
54 X=0?
55 GTO 00
56 X<0?
57 STO+ ST Y
58 SIGN
59 LASTX
60 NEWMAT
61 ATOX
62 STO+ ST Y
63 R↓
64 CLA
65 XTOA
66 R↓
67 AGRAPH
68 LASTX
69 ENTER
70 X>0?
71 SIGN
72 -
73▸LBL 00
74 +
75 END
76▸LBL "VLIND"
77 AON
78▸LBL "VLINE"
79 255
80 CLA
81 XTOA
82 FS? 48
83 XTOA
84 R↓
85 STO ST T
86 R↓
87 AOFF
88 REAL?
89 GTO 00
90 COMPLEX
91 X<>Y
92 AON
93▸LBL 00
94 X<>Y
95 R↑
96 X<0?
97 GTO 01
98 8
99 X≥Y?
100 GTO 00
101▸LBL 02
102 R↓
103 R↓
104 COMPLEX
105 AGRAPH
106 COMPLEX
107 R↓
108 R↓
109 STO+ ST Z
110 STO- ST Y
111 X ST L
118 -8
119 X≤Y?
120 GTO 00
121▸LBL 03
122 STO+ ST Z
123 R↓
124 R↓
125 COMPLEX
126 AGRAPH
127 COMPLEX
128 R↓
129 R↓
130 STO- ST Y
131 X>Y?
132 GTO 03
133▸LBL 00
134 R↓
135 X=0?
136 GTO 00
137 2
138 1/X
139 XY
142 Y↑X
143 DSE ST X
144 ALENG
145 X<>Y
146 CLA
147 XTOA
148 DSE ST Y
149 XTOA
150 R↓
151 R↓
152 LASTX
153 X<0?
154 STO+ ST Y
155 R↓
156 COMPLEX
157 AGRAPH
158 COMPLEX
159 R↑
160 ENTER
161 SIGN
162 -
163 X>0?
164 STO+ ST Y
165▸LBL 00
166 R↓
167 X<>Y
168 FC? 48
169 RTN
170 X<>Y
171 COMPLEX
172 AOFF
173 END
174▸LBL "GRID"
175 CLLCD
176 XEQ 14
177 COMPLEX
178 X<>Y
179 XEQ "HLINE"
180 COMPLEX
181 X<>Y
182 R↓
183 XEQ 14
184 X<>Y
185 COMPLEX
186 X<>Y
187 XEQ "VLINE"
188 RTN
189▸LBL 14
190 EDIT
191 SIGN
192 LASTX
193 ←
194 STO+ ST Y
195 EXITALL
196 X<>Y
197 LASTX
198 STO- ST Y
199 R↑
200 STO+ ST Y
201 STO- ST Y
202 END
203▸LBL "M×+"
204 9
205 1/X
206 1/X
207 FP
208 1/X
209 STO+ ST Y
210 STO+ ST Z
211 ÷
212 STO× ST Y
213 X<> ST L
214 -
215 END
216▸LBL "FILL"
217 1
218 ENTER
219 COMPLEX
220 +
221 RCL- ST Y
222 ALENG
223 ABS
224 CLX
225▸LBL 02
226 ATOX
227 XTOA
228 X>Y?
229 X<>Y
230 R↓
231 DSE ST L
232 GTO 02
233 LOG
234 2
235 LOG
236 ÷
237 IP
238 1
239 +
240▸LBL "FILLh"
241 X<>Y
242 COMPLEX
243 R↓
244 X<>Y
245 STO÷ ST T
246 COMPLEX
247 R↑
248 XEQ "M0N"
249 X<>Y
250 COMPLEX
251 X<>Y
252 R↓
253 ×
254 FP
255 LASTX
256 COMPLEX
257 XEQ "M×+"
258 X<>Y
259▸LBL 04
260 X<>Y
261 AGRAPH
262 X<>Y
263 ALENG
264 STO+ ST Z
265 -
266 X>0?
267 GTO 04
268 END
269▸LBL "M0N"
270 SIGN
271 LASTX
272 NEWMAT
273 EDIT
274 DSE ST L
275▸LBL 02
276 ←
277 LASTX
278 DSE ST L
279 GTO 02
280 EXITALL
281 END
282▸LBL "CHESS"
283 2
284 XEQ 14
285 CLLCD
286 9
287 XEQ "M0N"
288 13
289 ×
290 5
291 +
292 TRANS
293 EDIT
294 ENTER
295 INSR
296 SIGN
297 -
298 ←
299 GROW
300 ENTER
301 →
302 SIGN
303 +
304 EXITALL
305 ENTER
306 XEQ "GRID"
307 3
308 XEQ 14
309 CLA
310 85
311 XTOA
312 STO+ ST X
313 XTOA
314 ASTO ST X
315 ARCL ST X
316 ARCL ST X
317 ASTO ST X
318 ARCL ST X
319 ARCL ST X
320 ARCL ST X
321 4
322 XEQ "M0N"
323 52
324 ×
325 RCL ST X
326 11
327 +
328 TRANS
329 X<>Y
330 37
331 +
332 FP
333 LASTX
334 COMPLEX
335 XEQ "M×+"
336 STO "."
337 16
338 1
339 DIM "."
340 RCL "."
341 XEQ 13
342 RCL "."
343 CLV "."
344 COMPLEX
345 X<>Y
346 COMPLEX
347▸LBL 13
348 24
349 ENTER
350 COMPLEX
351 8
352 XEQ "FILLh"
353 RTN
354▸LBL 14
355 STO "GrMod"
356 END