Graph It aka Graph IT II aka Graph IT Enhanced - TXG 9517

Dieses Programm stellt eingegebene Werte wahlweise als
Säulen- oder als Kreis-Segment-Graphiken dar. Darüber
hinaus konnen Sie 2- oder 3-dimensional Funktionen auf dem
Bildschirm erscheinen lassen. Bestimmte Karrenz-Werte
lassen sich über Cursor und Steuerknüppel abrufen.

Developer: Original developer of the US release (CX4109): Lane Winner (uncredited). / Howard D. Siebenrock
According to source code (REM at line 0):
Side 1 of Tape 1 (“Graphit II -2D”): ENHANCMENTS BY HOWARD SIEBENROCK / REV 1.3 11-13-81 (Yes, including the typo at “ENHANCMENTS” ! 😉 )
Side 2 of Tape 1 (“Graphit II -3D”): ENHANCED BY HOWARD SIEBENROCK / REV 1.3 11-15-81
Side 1 of Tape 2 (“Balken – und Kreisdiagramme”): GRAPH IT BAR-PIE REV 0.1 7-5-80 / ENHANCED BY HOWARD SIEBENROCK REV. 1.3 11.13.81
Side 2 of Tape 2 (“Polardastellung”): GRAPH POL:REV 0.3 9-25-80 / ENHANCED BY HOWARD SIEBENROCK VES. 1.3 11-14-81

Date: 1981 according to cover and source code, 1983 according to booklet.
Distributed by: ATARI Elektronik Vertriebs GMBH, Bebelalee 10 – 2000 Hamburg 60
Dump: Download – Source Atarinside – .Cas for sides 1, 2, 3 and .Wav format for side 4 (There is some additional datas recorded at the end of tape 2/side2 that can’t be saved as a cas file).
Notes: Translation and enhancement of “Graph IT” – CX4109 – USA.
Atariwiki reports that another release was also made for Germany with a different source code of “GRAPH IT BAR-PIE” in 1982.
How to run:  Load .CAS or .WAV in your emulator (Altirra), boot to Basic, CLOAD and RUN. Enable Cassette SIO Patch if you don’t want to wait.
Other translations :
USA : “Enhancements to Graph It” – APX 20074 – 1982
Italy : “Grafica – DXT 4109 – 1984”

Rendering comparison (“Graphit II -3D” – side 2 of tape 1):

1 – Heart
Atari Formula : 5+​(‑sqr(​1-​x^​2-​(y-​abs(​x))^​2))*​cos(​30*​(1-​x^​2-​(y-​abs(​x))^​2))
Google Formula : 5 + (-sqrt(1-x^2-(y-abs(x))^2))*cos(30*((1-x^2-(y-abs(x))^2))), x is from -1 to 1, y is from -1 to 1.5, z is from 1 to 6

2 – Water drop
Atari Formula : sqr(x*x+y*y)+3*cos(sqr(x*x+y*y))+5
Google Formula : sqrt(x*x+y*y)+3*cos(sqrt(x*x+y*y))+5 from -20 to 20

3 – Egg
Atari Formula : 1.2+(sqr(1-(sqr(x^2+y^2))^2)+1–x^2-y^2)*(sin(10*(x*3+y/5+7))+1/4)
Google Formula : 1.2+(sqrt(1-(sqrt(x^2+y^2))^2)+1–x^2-y^2)*(sin(10*(x*3+y/5+7))+1/4) from -1.6 to 1.6

4 – Wheel

Atari Formula : (0.4^2-(0.6-(x^2+y^2)^0.5)^2)^0.5
Google Formula : (0.4^2-(0.6-(x^2+y^2)^0.5)^2)^0.5

5 – Pyramid

Atari Formula : 1-abs(x+y)-abs(y-x)
Google Formula : 1-abs(x+y)-abs(y-x)

6 – Waves

Atari Formula : x*sin(-(x*x)-(y*y))
Google Formula : x*sin(-(x*x)-(y*y)) from -5 to 5