vector initialPos;
float t = 0; // parameter, tracing out circle in radians
float r = 3; // radius of the circle in meters
float inc = 0.1; // increment in radians

default
{
    touch_start(integer n)
    {
        initialPos = llGetPos();
        llSetTimerEvent(0.01);
    }

    timer() // revolve in circular orbit
    {
        llSetPos((<llCos(t),llSin(t),0> * r) + initialPos);
        t = t+inc;
    }
}