Picture of the week is the 2D chemical formula of the 1,2-dimethyl-chickenwire molecule, noted by Wikipedia in several places (here and here).
The simplified LibreLogo program of the new Wikipedia vector graphic (move the turtle to the right side in Writer before starting the program):
TO hexagon REPEAT 6 [ FORWARD 25 RIGHT 360/6 ] END TO hexagons n REPEAT n [ hexagon PENUP FORWARD 75 PENDOWN ] END PICTURE “1,2-dimethyl-chickenwire.svg” [ FONTSIZE 20 PENSIZE 2 HIDETURTLE PENJOINT “MITER” hexagons 2 REPEAT 10 [ RIGHT 120 PENUP FORWARD 25 RIGHT 60 PENDOWN hexagons 3 RIGHT 120 PENUP FORWARD 2*25 LEFT 60 FORWARD 25 RIGHT 120 PENDOWN hexagons 4 PENUP BACK 25*3 ] PENUP FORWARD 25 LEFT 60 PENDOWN FORWARD 15 RIGHT 60 LABEL [-1.1, 0.4, “H₃C”] PENUP LEFT 60 BACK 15 RIGHT 120 FORWARD 25 LEFT 60 PENDOWN FORWARD 15 LABEL [0.6, 0.9, “CH₃”] PENUP BACK 15+25+25 LEFT 180 PENDOWN hexagons 3 RIGHT 120 PENUP FORWARD 3*25 RIGHT 60 FORWARD 2*25 PENDOWN hexagons 2 CLOSE ]
(For those interested, here are the steps to get one more dimension, the spatial model of 1,2-dimethyl-chickenwire, as you can see on the picture:
Copy the SMILES description of the molecule (see on its Wikipedia page, or here) into the PubChem Sketcher online molecule editor, and press Enter to show the molecule.
Export the picture in the default SDF (MDL Molfile) format.
Open the file in Avogadro, a cross-platform molecule editor (it is part of the popular Linux distributions), but do not ask the calculation of the 3D geometry.
Choose Build→Add Hydrogens. (It is possible in PDChem Sketcher, too, by Hydrogen→Add. In that case the result will be a nearly planar spatial isomer, thanks to the more evenly distributed hydrogens).
Press Ctrl-Alt-O (Extension→Optimize Geometry) a few times, moving the atoms to the positions defined by their bonds.
Finally export the picture of the molecule in PNG to LibreOffice, for example. It would be more fun to export it in a 3D OpenDocument shape, supported by LibreOffice, too, but it seems, chemical formula conversion tools, like Open Babel, haven’t supported OpenDocument, yet.)