integer active = 1;

default
{
    touch_start(integer num_detected)
    {
        if(!active)
        {
            llSetAlpha(1,ALL_SIDES);
            llMessageLinked(LINK_SET,-1,"1",NULL_KEY);
            active = 1;
        }
    }
    
    link_message(integer sender, integer num, string msg, key id)
    {
        if(num == -1 && msg != "1")
        {
            llSetAlpha(0.75,ALL_SIDES);
            active = 0;
        }
    }
}