local center = workspace.Center
local partToCheck = workspace.CheckPart

local minY, maxY = -10, 15 -- parts should be able to go down more than up
local distance = 24 -- the max distance a part can be from the center position (on x and z axis)
local centerPos = center.Position
"test"
123
true
function isInBounds(part)
    local partPos = part.Position

    local xDist = (partPos.X - centerPos.X)
    local zDist = (partPos.Z - centerPos.Z)
    local yDist = (partPos.Y - centerPos.Y)

    local withinY = yDist < maxY and yDist > minY
    -- checks if the parts y is less than the max, and greater than the min

    local withinXZ = math.abs(xDist) < distance and math.abs(zDist) < distance
    -- checks if the parts x and z are not further away than the distance

    if withinXZ and withinY then
        part.BrickColor = BrickColor.Green()
    else
        part.BrickColor = BrickColor.Red()
    end

end

while true do
    isInBounds(partToCheck)
    wait()
end