This has been put to the extreme by Chuck Moore [1]
> During the 1990s, he used his own CAD software to design several custom VLSI chips, including the F21 processor with a network interface. More recently, he invented colorForth and ported his VLSI design tools to it
> During the 1990s, he used his own CAD software to design several custom VLSI chips, including the F21 processor with a network interface. More recently, he invented colorForth and ported his VLSI design tools to it
[1] http://www.greenarraychips.com/home/about/bios.html