fcn mkRand(mean,sd){ //normally distributed random w/mean & standard deviation
   pi:=(0.0).pi;    // using the Box–Muller transform
   rz1:=fcn{1.0-(0.0).random(1)}  // from [0,1) to (0,1]
   return('wrap(){((-2.0*rz1().log()).sqrt() * (2.0*pi*rz1()).cos())*sd + mean })
}