If [your piece] is inside your head like a marble rolling around, it will come out that way, College of Southern Maryland Jazz Fest guest artist Bobby Shew, right, told members of North Point High Schools jazz band on April 4 in La Plata. With fingers playing an imaginary instrument and arms waving, Shew, a multiple Grammy Award winning trumpeter, gave students pointers that he said took him a lifetime to learn. Later in the morning Shew challenged the Northern High School jazz band students to turn their music over and play from memory. If you memorize it, you own it. If it is on paper, the paper owns it, he said. Earlier in the week, Shew visited jazz bands from McDonough and La Plata high schools.