text: const holderJoin = () => {
    const mainKnobDia = 10
    const frictionKnobsDia = 2
    const frictionKnobsCount = 12
  
    const mainKnob = sphere({r: mainKnobDia / 2})
    const frictionKnobs = 
  
    return union(
      mainKnob,
  
    )
  }
  