Codify Particle script. Use single touch to make particles go away from you. Use double touch to attract particles.

Codify Particle.lua

p={}
ps=800
touches={}
total=0
-- Use this function to perform your initial setup
function setup()
 print("Hello World!")
 for i=0,ps do
     p[i]= {x=math.random(WIDTH*10)/10,
y=math.random(HEIGHT*10)/10, ox=0.0, oy=0.0, vx=math.random(20)-10,
vy=math.random(20)-10, prevX=0, prevY=0}
   p[i].prevX=p[i].vx
       p[i].prevY=p[i].vy
 end
end

-- This function gets called once every frame
function draw()
   --print(ElapsedTime)
 noSmooth()

 background(10,10,20)
 fill(255,0,0)
 stroke(255, 255, 255, 255)
 strokeWidth(4)

 --t={x=CurrentTouch.x , y=CurrentTouch.y}
 --if t.x ~= CurrentTouch.prevX and t.y ~= CurrentTouch.prevY then
 --    touchy(t,0)
 --end
--    print(total)

--  for i=0,ps do
--        p[i].vx=p[i].prevX
--        p[i].vy=p[i].prevY
--  end
 if total == 1 then
    for k,touch in pairs(touches) do
       touchy(touch,1)
       end
 elseif total == 2 then
   t={}
   i=0
   for k,touch in pairs(touches) do
       --touchy(touch,1)
       t[i]=touch
       i = i + 1
   end

   endTouch={x=(t[0].x+t[1].x)/2,y=(t[0].y+t[1].y)/2}
   touchy(endTouch,0)

 --elseif total==3 then
 --  for i=0,ps do
 --      p[i].prevX=p[i].vx
  --     p[i].prevY=p[i].vy
 --      p[i].vx=0
 --      p[i].vy=0
   --end

 end

   for k,touch in pairs(touches) do
       -- Use the touch id as the random seed
       math.randomseed(touch.id)
       -- This ensures the same fill color is used for the same id
       fill(math.random(255),math.random(255),math.random(255))
       -- Draw ellipse at touch position
       ellipse(touch.x, touch.y, 100, 100)
   end

 for i=0,ps do
     p[i].ox= p[i].x
     p[i].oy= p[i].y
     p[i].x = p[i].x + p[i].vx
     p[i].y = p[i].y + p[i].vy


     if p[i].x<0 then
         p[i].x=0
         p[i].vx= -p[i].vx
     end

     if p[i].y<0 then
         p[i].y=0
         p[i].vy= -p[i].vy
     end

     if p[i].x>WIDTH then
         p[i].x=WIDTH
         p[i].vx= -p[i].vx
     end

     if p[i].y>HEIGHT then
         p[i].y=HEIGHT
         p[i].vy= -p[i].vy
     end

     p[i].vx = p[i].vx*0.97
     p[i].vy = p[i].vy*0.97
     stroke(math.random(255),math.random(255),math.random(255),255)
     line(p[i].ox, p[i].oy, p[i].x, p[i].y)
 end
end

function touchy(t,g)
 a=5
 for i=0,ps do
     d= (p[i].x-t.x)*(p[i].x-t.x) + (p[i].y-t.y)*(p[i].y-t.y)
     d= math.sqrt(d)
     if g==0 then
         p[i].vx = p[i].vx - a/d*(p[i].x-t.x)
         p[i].vy = p[i].vy - a/d*(p[i].y-t.y)
       else
           p[i].vx = p[i].vx + a/d*(p[i].x-t.x)
         p[i].vy = p[i].vy + a/d*(p[i].y-t.y)
       end

 end
end

function touched(touch)
   if touch.state == ENDED then
       table.remove(touches,touch.id)
       touches[touch.id]=nil
       if total ~= 0 then
           total = total - 1
       end
   else
       if touches[touch.id]== nil then
           total = total + 1
       end
       touches[touch.id] = touch

   end
   if touch.state == BEGAN then
       sound("jump",math.random(255))
   end
end