blue circle isn't drawing and print isn't working?

[SMcNeill]

It's single because that's the default type for an unsuffixed variable not explicitly DIMmed as something else. 
The default can be changed with the DEF{type} command, e.g., DEFLNG for long. 
Is that right?

Exactly. And that's basically what your original issue was. You had this basic code:

DIM x~&
x = 123

So the x you were using was SINGLE (which won't hold blue color channels due to rounding in scientific notation), even though all your DIM statements were for x~&.

Option Explicit would've caught the issue for you in a second.

[TerryRitchie]

Option Explicit would've caught the issue for you in a second. 

The very reason I never program without OPTION _EXPLICIT as the first line of code.

[madscijr]

Option Explicit would've caught the issue for you in a second. 

The very reason I never program without OPTION _EXPLICIT as the first line of code.

I usually use it myself, was just rushing here! 
It's a very helpful tool for avoiding some of these issues right out of the gate.