A script with all the examples can be found here. Just call the command above to image to see the effect.
To stop all effects type: /stopeffect
/color-circles
Shows circles with random colors. Could be used for a teleportation effect.

/line-circle

/line-circle-2

/line-vortex

/line-vortex-2

/miniblock-halo <integer>
Note: This is a quite advanced example. You can choose the amount of miniblocks with the integer parameter.

/rainbow-lines

/rainbow-halo
Halo follows the rotation of the player's head

/rainbow-yaw-helix
Color changes depending on the yaw of the player

/star <integer>
Simple star shape. You can change the amount of vertices with the integer parameter.

/star-2 <integer>
Makes a star with more connections than /star. You can change the amount of vertices with the integer parameter.

/star-player <integer>
Makes a star that is always oriented towards the player. You can change the amount of vertices with the integer parameter.
