$fs=.25;$fa=1;
h=80;
b=40;
w=1;
rad=30;

//3D
 //linear_extrude(w)Plate();
 
//2D
 Plate();
 
module Plate()
 difference(){
    hull(){
      translate([h-rad,b-rad/2])scale([1,.5])circle(rad);
      square([h-rad,b]);
      square([h,b-rad/2]);
    }
    for(x=[0:h/7],y=[0:b/6-x/8])translate([x*6,y*5]+(y%2?[3,0]:[0,0])+[5,4])rotate(30)offset(1)circle(d=3,$fn=6);
  }