$fn=50;

alpha = 0.5;

rc = 2.4; //rayon des cylindres

sep = 3.2 ;
n_hole = 9 ;
n_out1 = 2 ;
n_out2 = 2;
n_out = n_out1+n_out2;
lon = (n_hole+n_out)*(2*rc + sep) - sep + 2*sep*alpha; // longueur du cube
la = 2*(rc+sep*alpha); //largeur du cube
ha = la; // hauteur du cube 

ha_trou = la*1.5; // hauteur des cylindres formant les trous
ha_cyl = la/4; // hauteur des cylindres

union(){

//       translate([2*rc+sep*alpha+0.5*sep,la/2,0])
//    for( i = [0:n_hole+n_out-2]) {
//       translate([i*(2*rc + sep),0,(1.5*sep*alpha+2*rc)]) 
//       cylinder(h=ha_cyl+(sep*alpha*0.5), r=rc); 
//      }

    difference(){
        cube([lon,la,ha]);
        translate([rc+sep*alpha,la,ha/2])
        for (i=[n_out1:n_out1+n_hole-1]){
            translate([i*(2*rc + sep),0,0])
            rotate([90,0,0])cylinder(h=ha_trou, r=rc);
        }
    }    

    translate([rc+sep*alpha,sep*alpha*0.5,ha/2])
    for (i=[0:n_out1-1]){
        translate([i*(2*rc + sep),0,0])
        rotate([90,0,0])
        cylinder(h=ha_cyl+(sep*alpha*0.5),r=rc); 
    }
    
        translate([rc+sep*alpha,sep*alpha*0.5,ha/2])
    for (i=[n_hole+n_out1:n_hole+n_out-1]){
        translate([i*(2*rc + sep),0,0])
        rotate([90,0,0])
        cylinder(h=ha_cyl+(sep*alpha*0.5),r=rc); 
    }
}