Particles.Arcade.Emitter#createMultiple()

Creates multiple Phaser.Sprite objects and adds them to the top of this Group.

This method is useful if you need to quickly generate a pool of sprites, such as bullets.

Use classType to change the type of object created.

You can provide an array as the key and / or frame arguments. When you do this
it will create quantity Sprites for every key (and frame) in the arrays.

For example:

createMultiple(25, ['ball', 'carrot'])

In the above code there are 2 keys (ball and carrot) which means that 50 sprites will be
created in total, 25 of each. You can also have the frame as an array:

createMultiple(5, 'bricks', [0, 1, 2, 3])

In the above there is one key (bricks), which is a sprite sheet. The frames array tells
this method to use frames 0, 1, 2 and 3. So in total it will create 20 sprites, because
the quantity was set to 5, so that is 5 brick sprites of frame 0, 5 brick sprites with
frame 1, and so on.

If you set both the key and frame arguments to be arrays then understand it will create
a total quantity of sprites equal to the size of both arrays times each other. I.e.:

createMultiple(20, ['diamonds', 'balls'], [0, 1, 2])

The above will create 20 'diamonds' of frame 0, 20 with frame 1 and 20 with frame 2.
It will then create 20 'balls' of frame 0, 20 with frame 1 and 20 with frame 2.
In total it will have created 120 sprites.

By default the Sprites will have their exists property set to false, and they will be
positioned at 0x0, relative to the Group.x / y values.

If Group.enableBody is set, then a physics body will be created on the objects, so long as one does not already exist.

If Group.inputEnableChildren is set, then an Input Handler will be created on the objects, so long as one does not already exist.