You don't have to draw a huge circle, just draw one pixle of any ray element.
Remember that spark does not have direction, so the ray elements just check their surroundings for spark, and shoot in the opposite direction.
Build something like this:
(M=METL, A=ARAY, B=BRAY, S=SPRK)
By frame:
SMMMA
SSMMA
SSSMA
SSSSA
MSSSABBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB (and so forth)
However, if you have metl going diagonal,
A
S
B (and so forth)
B
B
A
S
So when you have more than 1 metl conducting to ARAY, you get this.
SA
S
B (and so forth)
B
B
SABBBBBBBBBBBBBBB (and so forth)
S
This is a result of aray seeing two sparks, one to the left and one to the bottom left, so it shoots opposite to both sparks, up right and right.