Processing has been mentioned upstream, and is easy enough to do most of what you put forth.

Racket is also good for this [1,2]:

    #lang slideshow
    (circle 10)

or in 3d:

    #lang racket
    (require pict3d)
    (sphere origin 1/2)

I have been in a time vortex playing with Raylib [3], a C-based game environment that is cross platform, easy to setup and comes with plenty of examples. I have modified the included game examples, and created a Windows .exe, an Android apk, and a web-based version (via Emscripten) with no hassles.

Disclaimer: I am not a gamer, but the area of games brings a lot of the things I am interested in to study. I am also interested in NetLogo for simulations and the subject of 'serious games', or 'applied games', which are not a bash on recreational gaming, but a name for games used in things like civic planning, scientific exploration, or basically simulations vs. entertainment.

I am now onto putting some long-forgotten knowledge to use again in reimplementing AI search algorithms, sorting and data structures. It is motivating. Raylib is a pretty simple, yet functional setup for me.

[1] https://docs.racket-lang.org/pict/

[2] https://github.com/ntoronto/pict3d

[3] http://www.raylib.com/

I learned programming in flash with as2 a little and then as3, and I feel that is still the easiest way to learn programming, you convert your symbols into classes and bam, in two seconds you're doing OOP, setting properties and calling methods (like play() stop()), it even helped me find the use of sines and cosines because it wasn't clear how trigonometry was useful back in school. I find it easier to learn the concrete stuff first, and then go to the abstract.

It's fairly easy now with a little Javascript and some html knowledge.