$fn=25;

x = 20;
y = 10;
z = 10;
wall = 2;
bottom = 1;

difference() {
    minkowski(){
        cube([x+wall,y+wall,z+bottom], center=true);
        cylinder();
    }
    
    translate([0,0,bottom])
     minkowski(){
        cube([x,y,z], center=true);
        cylinder();
     }
        


translate([0,0,(z/2)]){
    linear_extrude(height=1.5){
        minkowski(){
        square([x+(wall/2),y+(wall/2)], center=true);
        circle();
        }
    }
}
}







translate([x+10,0,2.5])
rotate([180,1,0])
difference() {
    difference(){
        translate([0,0,z/2+1])
        minkowski(){
            cube([x+wall,y+wall,2],center=true);
            cylinder();
        }
        difference() {
        minkowski(){
            cube([x+wall,y+wall,z+bottom], center=true);
            cylinder();
        }
        
        translate([0,0,bottom])
         minkowski(){
            cube([x,y,z], center=true);
            cylinder();
         }
            
    
    
    translate([0,0,(z/2)]){
        linear_extrude(height=1.5){
            minkowski(){
            square([x+(wall/2),y+(wall/2)], center=true);
            circle();
            }
        }
    }
    }
    
        
        cube([x+wall/2,y+wall/2,z+5],center=true);
    cylinder(z*2,2,2,$fn=5, center=true);

}
}