Free vs. Special vs. Rare vs. Bell Summon(s)

The difference between Free Summon vs. Special Summon vs. Rare Summon vs. Bell Summon = The colour and pattern of the magical summoning circle (魔法阵) that appears on the floor during the summoning process.
[I personally did not attempt any Bell Summon before; screenshot was provided by a friend.]

Free Summon: Blue magical summoning circle.

[The daemon card would appear from the midst of the summoning circle.]

Special Summon: Lilac magical summoning circle.

[The summoning circle certainly appears to be bigger now.]

Rare Summon: Gold magical summoning circle.

[Golden lightning and electric sparks during the summoning process! o.O]

Bell Summon: Lilac magical summoning circle.

[Resembles Special Summon, but with the presence of a ringing bell + lilac lightning and electric sparks! O.o]

It seems that only Free Summon has the simplest design and smallest magical summoning circle, compared to the more complex-looking design (looks more powerful too) and bigger magical summoning circles in Special, Rare and Bell Summons.

~ Loves, Ayumi-san :)