layer =
layer 0
-extend -midx_x_bl -midx_sc_a len 10 315
-part midx_sc pt_peco_sl a
+extend -midx_x_bl -midx_j_a len 10 315
+part midx_j pt_peco_sl a
-extend -midx_sc_c -bot_0lm_b parallel demos!right_main_up 315
+extend -midx_j_c -bot_0lm_b parallel demos!right_main_up 315
part bot_0lm ^pt_main_r b
extend -bot_0lm_c -leb_0k uptoang 90 315
extend high_6br0 high_6br1 ang 90 -230
join -sta_67r_c high_6br0 230
-extend -sta_6far -sta_6nears len 600
+extend -sta_6far -sta_6nears len 630
part sta_67l pt_peco_sl b sta_6nears
join sta_67l_a -sta_67r_b 230
extend -sta_67l_c high_6bl5 uptoang 90 230
-layer p10
+layer p20
+
+rel sta_6nears sta_6nears_platnear 0 -14.5
+rel sta_6nears_platnear sta_6nears_platfar 0 -17
+extend sta_6nears_platnear sta_6far_platnear upto sta_6far
+extend sta_6nears_platfar sta_6far_platfar upto sta_6far
+join sta_6nears_platnear -sta_6nears_platfar 1
+join sta_6far_platnear -sta_6far_platfar 1
# medium-level platforms
+layer p10
+
rel sta_4far sta_4far_platnear 0 -14.5
rel sta_4far_platnear sta_4far_platfar 0 -17
extend -sta_4far_platnear -sta_4neare_plat upto sta_4neare
extend sta_3neare sta_3y0_c uptoang 5 -230
part sta_3y0 pt_peco_sl c
-layer 8
-extend sta_3sc_b -leb_0sc uptoang 90 300
-
# junctions
layer 10
extend sta_3y0_b sta_0y1_c ang 1 -230
part sta_0y1 pt_peco_sl c
-layer 12
-extend sta_0y1_b h_8b ang 90 -230
-
layer 10
rel sta_4neare sta_3nears 280 -46
part sta_3y1 pt_peco_sl c sta_3y0_a
join sta_1far sta_tt_in 230
join sta_2y0_a sta_1far 230 arcline
+#---------- sort-of helix (regions sc and h)
+
+layer 0
+extend midx_j_b sc_9 len 80 -230
+
+layer 5
+rel top_0lm_c -sc_7 0 40
+
+layer 2
+extend -sc_7 -sc_8 ang 45 315
+join sc_9 sc_8 315
+
+layer 8
+extend sc_7 sc_6 ang 60 -275
+extend sta_3sc_b -sc_3 len 20 -450
+extend -sc_3 -sc_5 len 50 230
+join sc_6 sc_5 230
+
+layer 12
+extend sta_0y1_b high_6s0 ang 65 -230
+extend high_6s0 high_6s1 uptoang 0 230
+
#---------- shunting yard
layer 10