summon armor_stand ~ ~ ~ {Glowing:1,NoGravity:1}

scoreboard players set #a lim 360
function bktsb:rng
execute store result entity @e[type=armor_stand,sort=nearest,nbt={Glowing:1b},tag=!ame_rays,limit=1] Rotation[0] float 1.0 run scoreboard players get #a randr

scoreboard players set #a lim 181
function bktsb:rng
scoreboard players set #a lim 90
scoreboard players operation #a randr -= #a lim
execute store result entity @e[type=armor_stand,sort=nearest,nbt={Glowing:1b},tag=!ame_rays,limit=1] Rotation[1] float 1.0 run scoreboard players get #a randr

tag @e[type=armor_stand,sort=nearest,nbt={Glowing:1b},tag=!ame_rays,limit=1] add ame_rays