One function to draw a lot of circles? On what basis are drawn bullets?

i think you want circ or circfill. from the manual:

    circ     x y r [col]
    circfill x y r [col]

        Draw a circle or filled circle at x,y with radius r

or did you want something more involved?

No, I'm creating a function, but it draws a circle once and clean, but I need to circle all remained.

Just a code consisting only of circ (), circ (), circ() - stupid.

may be to create an array and store the coordinates there ...

i don't understand. what do you need multiple circ calls for?

function random_circles(number)
  for i=1, number do
    circ( rnd(127), rnd(127), 10)
  end
end

Something like that? If you want the circles to be able to move like bullets you need to make a data structure to keep track of each circle's data.

maybe you want to show bullet's trail like matrix style? You should consider creating simple particle system then, create and store each particle in array and call draw method for each one in the _draw call