Rez several copies of the object on the ground and each section will connect to the last one rezed. Delete an object to break the connections.
Choose "resettarget" in dialog menu then rez a new object and all previous objects are connected to the new rezzed one.
Type "/66change" and a menu will drop down allowing you to choose 12 colors or 3 sizes.
Caution: If you choose "finalize" in dialog box then the color and size is fixed. (even if you type "/66change", dialog box won't drop down) If you delete the last rezzed object then menu won't drop down, but you can still change the colour or size with voice commands.
You can also use voice commands on channel 66, as follows:
/66 finalize /66 resettexture /66 resettarget /66 fine /66 normal /66 bold /66 white /66 gray /66 black /66 blue /66 red /66 green /66 yellow /66 pink /66 cyan /66 magenta /66 lavender /66 rainbow
Texture: /66 texture UUID - UUID is the UUID of the texture you want to use. To obtain that key, find the texture you want to use in your inventory, right click it, and choose 'Copy Asset UUID', and then ctrl+v, it'll get you the desired key. The command will look like this: '/66 texture c6dbc4b2-918c-b224-8f8d-210b9a07fabf' If you choose "resettexture" in dialog menu, it will revert to the default texture.
Size: /66 size VALUE - changes the size of the particles, range 0.03125 - 4.0. (default size is fine - 0.1, normal - 0.2, bold - 0.3) The command will look like this: '/66 size 0.1'
Rainbow Color Interval: /66 time VALUE - changes the color change interval of the particles when "rainbow" is selected in dialog menu. (default interval is 3.0) The command will look like this: '/66 time 1.0'