At work we built a BI tool around Blockly in 2013. Still in daily use: https://www.dialogic.nl/wp-content/uploads/2018/02/demo1.gif
The interface designer in me immediately wants to scream "Fitt's Law!"¹ and move the header with run/select/save from above the output to between the output and the code blocks though.
EDIT: Actually, Fitt's Law tells us not to do that. But scrolling to find those buttons is also wrong. Why not make it a sticky header?
¹ https://www.interaction-design.org/literature/topics/fitts-l...
When designing interfaces for a screen, the edges (assuming that moving the mouse to the edge doesn't cause scrolling) can be considered "infinitely" wide or tall for the purpose of Fitt's law. This is a really old insight:
https://www.joelonsoftware.com/2000/04/27/designing-for-peop...
Pressing your card against the card reader is the same idea: you don't have to be precise with your motor functions, because as soon as you hit the card reader you know you're close enough. So people can be faster with this approach.
(with that in mind, my earlier solution is actually wrong: the buttons shouldn't be put between the output and the code, they should be made sticky)