Sparks was drawn in Robofont (1.8.4), though a considerable amount of work was done to the dot-line UFO files in a text editor.
Due to the nature of the dot-line chart glyphs, once the primitives were drawn most of the work to create the full glyph set was done by directly editing the contents of the UFO files with a text editor. Some fancy find-and-replace was enough to create the glyph list (which is part of lib.plist) and the actual .glif files were generated by a Python script generously written by Owen Praeger.
All of the fonts were processed with ufonormalize and then output from Robofont. (Output of OTF files for the dotline UFOs takes a long time, i.e. 10 minutes per file.) The webfont files (woff, woff2, eot, svg) were generated using the Batch plugin. After generation all fonts were checked with OTS.