Examples from the Graphviz gallery.
graph 1 3 5.5556 node a0 0.875 4.25 0.75 0.5 a0 filled ellipse white white node a1 0.875 3.25 0.75 0.5 a1 filled ellipse white white node a2 0.875 2.25 0.75 0.5 a2 filled ellipse white white node a3 0.875 1.25 0.75 0.5 a3 filled ellipse white white node b0 2.3611 4.25 0.75 0.5 b0 filled ellipse black lightgrey node b1 2.375 3.25 0.75 0.5 b1 filled ellipse black lightgrey node b2 2.4028 2.25 0.75 0.5 b2 filled ellipse black lightgrey node b3 2.3333 1.25 0.75 0.5 b3 filled ellipse black lightgrey node start 1.6111 5.3056 1.0866 0.5 start solid Mdiamond black lightgrey node end 1.5972 0.25 0.50298 0.50298 end solid Msquare black lightgrey edge a0 a1 4 0.875 3.9958 0.875 3.8886 0.875 3.7599 0.875 3.6405 solid black edge a1 a2 4 0.875 2.9958 0.875 2.8886 0.875 2.7599 0.875 2.6405 solid black edge a1 b3 4 1.0338 3.0213 1.2881 2.6775 1.7882 2.0011 2.0884 1.5951 solid black edge a2 a3 4 0.875 1.9958 0.875 1.8886 0.875 1.7599 0.875 1.6405 solid black edge a3 a0 10 0.68402 1.4713 0.56999 1.6097 0.43585 1.8021 0.375 2 0.17905 2.6372 0.17905 2.8628 0.375 3.5 0.42064 3.6484 0.5075 3.7937 0.59619 3.9155 solid black edge a3 end 4 1.0353 1.0203 1.1227 0.90265 1.2332 0.75397 1.333 0.61963 solid black edge b0 b1 4 2.3645 3.9958 2.3661 3.8886 2.3679 3.7599 2.3696 3.6405 solid black edge b1 b2 4 2.3819 2.9958 2.3849 2.8886 2.3886 2.7599 2.392 2.6405 solid black edge b2 a3 4 2.1367 2.0668 1.8935 1.912 1.5311 1.6814 1.257 1.507 solid black edge b2 b3 4 2.3856 1.9958 2.378 1.8886 2.3688 1.7599 2.3602 1.6405 solid black edge b3 end 4 2.17 1.0203 2.0809 0.90265 1.9683 0.75397 1.8666 0.61963 solid black edge start a0 4 1.4829 5.1126 1.3805 4.9697 1.2342 4.7654 1.1108 4.5931 solid black edge start b0 4 1.7418 5.1126 1.8461 4.9697 1.9951 4.7654 2.1209 4.5931 solid black stop
digraph G { node [label="\N"]; graph [bb="0,0,216,400", _draw_="c 9 -#ffffffff C 9 -#ffffffff P 4 0 -1 0 400 217 400 217 -1 ", xdotversion="1.2"]; subgraph cluster_0 { graph [style=filled, color=lightgrey, label="process #1", bb="8,64,98,356", _draw_="c 9 -#d3d3d3ff C 9 -#d3d3d3ff P 4 8 64 8 356 98 356 98 64 ", _ldraw_="F 14.000000 11 -Times-Roman c 9 -#000000ff T 53 338 0 59 10 -process #1 ", xdotversion=""]; node [style=filled, color=white]; a0 [pos="63,306", width="0.75", height="0.5", _draw_="c 9 -#ffffffff C 9 -#ffffffff E 63 306 27 18 ", _ldraw_="F 14.000000 11 -Times-Roman c 9 -#000000ff T 63 300 0 13 2 -a0 "]; a1 [pos="63,234", width="0.75", height="0.5", _draw_="c 9 -#ffffffff C 9 -#ffffffff E 63 234 27 18 ", _ldraw_="F 14.000000 11 -Times-Roman c 9 -#000000ff T 63 228 0 13 2 -a1 "]; a2 [pos="63,162", width="0.75", height="0.5", _draw_="c 9 -#ffffffff C 9 -#ffffffff E 63 162 27 18 ", _ldraw_="F 14.000000 11 -Times-Roman c 9 -#000000ff T 63 156 0 13 2 -a2 "]; a3 [pos="63,90", width="0.75", height="0.5", _draw_="c 9 -#ffffffff C 9 -#ffffffff E 63 90 27 18 ", _ldraw_="F 14.000000 11 -Times-Roman c 9 -#000000ff T 63 84 0 13 2 -a3 "]; a0 -> a1 [pos="e,63,252.1 63,287.7 63,279.98 63,270.71 63,262.11", _draw_="c 9 -#000000ff B 4 63 288 63 280 63 271 63 262 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 67 262 63 252 60 262 "]; a1 -> a2 [pos="e,63,180.1 63,215.7 63,207.98 63,198.71 63,190.11", _draw_="c 9 -#000000ff B 4 63 216 63 208 63 199 63 190 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 67 190 63 180 60 190 "]; a2 -> a3 [pos="e,63,108.1 63,143.7 63,135.98 63,126.71 63,118.11", _draw_="c 9 -#000000ff B 4 63 144 63 136 63 127 63 118 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 67 118 63 108 60 118 "]; a3 -> a0 [pos="e,49.25,290.07 49.25,105.93 41.039,115.9 31.381,129.75 27,144 12.892,189.88 12.892,206.12 27,252 30.286,262.69 36.54,273.15 42.925\ ,281.92", _draw_="c 9 -#000000ff B 10 49 106 41 116 31 130 27 144 13 190 13 206 27 252 30 263 37 273 43 282 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 40 284 49 290 46 280 "]; } subgraph cluster_1 { graph [color=blue, label="process #2", bb="133,64,208,356", _draw_="c 9 -#0000ffff p 4 133 64 133 356 208 356 208 64 ", _ldraw_="F 14.000000 11 -Times-Roman c 9 -#000000ff T 171 338 0 59 10 -process #2 ", xdotversion=""]; node [style=filled]; b0 [pos="170,306", width="0.75", height="0.5", _draw_="c 9 -#000000ff C 9 -#d3d3d3ff E 170 306 27 18 ", _ldraw_="F 14.000000 11 -Times-Roman c 9 -#000000ff T 170 300 0 14 2 -b0 "]; b1 [pos="171,234", width="0.75", height="0.5", _draw_="c 9 -#000000ff C 9 -#d3d3d3ff E 171 234 27 18 ", _ldraw_="F 14.000000 11 -Times-Roman c 9 -#000000ff T 171 228 0 14 2 -b1 "]; b2 [pos="173,162", width="0.75", height="0.5", _draw_="c 9 -#000000ff C 9 -#d3d3d3ff E 173 162 27 18 ", _ldraw_="F 14.000000 11 -Times-Roman c 9 -#000000ff T 173 156 0 14 2 -b2 "]; b3 [pos="168,90", width="0.75", height="0.5", _draw_="c 9 -#000000ff C 9 -#d3d3d3ff E 168 90 27 18 ", _ldraw_="F 14.000000 11 -Times-Roman c 9 -#000000ff T 168 84 0 14 2 -b3 "]; b0 -> b1 [pos="e,170.76,252.1 170.25,287.7 170.36,279.98 170.49,270.71 170.61,262.11", _draw_="c 9 -#000000ff B 4 170 288 170 280 170 271 171 262 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 174 262 171 252 167 262 "]; b1 -> b2 [pos="e,172.51,180.1 171.49,215.7 171.71,207.98 171.98,198.71 172.23,190.11", _draw_="c 9 -#000000ff B 4 171 216 172 208 172 199 172 190 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 176 190 173 180 169 190 "]; b2 -> b3 [pos="e,169.22,108.1 171.76,143.7 171.21,135.98 170.55,126.71 169.94,118.11", _draw_="c 9 -#000000ff B 4 172 144 171 136 171 127 170 118 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 173 118 169 108 166 118 "]; } start [shape=Mdiamond, pos="116,382", width="1.085", height="0.5", _draw_="c 9 -#000000ff p 4 116 400 77 382 116 364 155 382 c 9 -#000000ff L 2 88 387 88 377 c 9 -#000000ff L 2 105 369 127 369 c 9 -#000000ff\ L 2 144 377 144 387 c 9 -#000000ff L 2 127 395 105 395 ", _ldraw_="F 14.000000 11 -Times-Roman c 9 -#000000ff T 116 376 0 24 5 -start "]; end [shape=Msquare, pos="115,18", width="0.50149", height="0.50298", _draw_="c 9 -#000000ff p 4 133 36 97 36 97 0 133 0 c 9 -#000000ff L 2 109 36 97 24 c 9 -#000000ff L 2 97 12 109 0 c 9 -#000000ff L 2 121\ 0 133 12 c 9 -#000000ff L 2 133 24 121 36 ", _ldraw_="F 14.000000 11 -Times-Roman c 9 -#000000ff T 115 12 0 20 3 -end "]; start -> a0 [pos="e,74.147,322.56 106.77,368.11 99.394,357.81 88.861,343.11 79.976,330.7", _draw_="c 9 -#000000ff B 4 107 368 99 358 89 343 80 331 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 83 329 74 323 77 333 "]; start -> b0 [pos="e,158.64,322.56 125.41,368.11 132.92,357.81 143.65,343.11 152.7,330.7", _draw_="c 9 -#000000ff B 4 125 368 133 358 144 343 153 331 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 156 333 159 323 150 329 "]; a1 -> b3 [pos="e,156.58,106.45 74.437,217.53 92.741,192.78 128.75,144.08 150.37,114.85", _draw_="c 9 -#000000ff B 4 74 218 93 193 129 144 150 115 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 153 117 157 106 148 112 "]; b2 -> a3 [pos="e,81.941,103.05 153.84,148.81 136.33,137.67 110.24,121.06 90.507,108.5", _draw_="c 9 -#000000ff B 4 154 149 136 138 110 121 91 109 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 92 105 82 103 88 111 "]; a3 -> end [pos="e,102.03,36.461 74.54,73.465 80.835,64.991 88.788,54.286 95.973,44.613", _draw_="c 9 -#000000ff B 4 75 73 81 65 89 54 96 45 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 99 47 102 36 93 42 "]; b3 -> end [pos="e,128.22,36.461 156.24,73.465 149.82,64.991 141.72,54.286 134.39,44.613", _draw_="c 9 -#000000ff B 4 156 73 150 65 142 54 134 45 ", _hdraw_="S 5 -solid c 9 -#000000ff C 9 -#000000ff P 3 137 42 128 36 131 47 "]; }