how to spawn random objects

Getting Started Newbie Questions
#1

Hey guys i have a  small and simple question how do i spawn random objects with this code

local physics = require (“physics”);

physics.start();

local function listener(me)

    transition.to (me, {time = math.random(1000,4000), x = math.random(10,310), y = -30, onComplete = function()listener(me)end});

end

–Spawning multiple objects in randoms locations

local function spawnblcok()

    local block = display.newImageRect(“block01.png”, 45, 45); – should i put a table here and  make it                                                                                                                                          pick a random block 

    block:setReferencePoint(display.CenterReferencePoint);

    block.x = math.random(-10, 300);

    block.y = -40;

    transition.to( block, {time = math.random(2000, 8000), x = math.random(-10, 400) , y = 600,});

    physics.addBody(block, “dynamic”, {density = 0.1, bounce = 0.1, friction = .1, radius = 0});

    --Adding touch event

    block:addEventListener(“touch”, block);

end

local total_block = 15

tmr = timer.performWithDelay(1000, spawnblcok, total_block);

also how do i make the block destroy their self when they  past the bottom of the screen 

thanks i really need this  i think its easy to fix but i can’t crack it  HELP  THANKS AGAIN :slight_smile: