Every block in a drawing has a scale. With the property palette it's easy to give all blocks the same scale, just enter a value at X, Y and X scale. With 'Scale Random' you can do the opposite. You can make a selection of blocks of which you want to change the scale. In the main menu of the command you can specify how the blocks should be scaled. By default the command will use the min and max method. With this method you can define a minimum and a maximum. For every block the command will randomly pick a value between these two values and will apply it to the block. You can also use the list method. In that case you can define a list of values. The command will pick a value randomly from that list and apply it to the block. So with a few clicks you can randomise the scale of your blocks.