The answer is none

You asked which symbol I invented and the answer is none.

The 220 keys on the Fitaly panels are the symbols of the Ascii/Ansi character set. They include the basic Ansi character set with codes 0-127 and the Latin-1 Supplement, with codes 128-255.

The choice of which characters to include in the Latin 1 supplement must have been made in one of those meetings where the French argued for accents, the German for umlaut and sz ligature, and the Icelandic would have found ways to block the decision if the eth and the thorn were not included. (The Turks must have been absent at that meeting and did not get their own characters :)

Jean Ichbiah