example rotate extrude three shape

bassiz = 4;
baspos=[7,0,0]; // [-30:.5:30]
bassca=[1,1,1]; // [0,001:.1:3.0]
basfn = 0;      // [0:50]
bascon= 2;      // [2:20]

rotang=360;     // [-400:10:400]
rotsta=  0;     // [-400:20:400]
rotfn =  0;     // [0:50]
rotcon=  2;     // [2:20]
rotgiv=true;

/* [Hidden] */
$fa=.5;
$fs=1;

module base_shape() {
    translate(baspos){
            square(bassiz);
        translate(baspos*1.5)
            scale( bassca )
            circle(bassiz, $fn=basfn);
        }
    children();
    }
color("red")
    base_shape();
color("yellow")
    rotate([90,0,0]) base_shape();

//if( rotfn % 2 !=0 )
    //rotate(180)

if( rotgiv )
    %rotate_extrude( a=rotang, start=rotsta, convexity=rotcon, $fn=rotfn )
        base_shape();
else
    %rotate_extrude( convexity=rotcon, $fn=rotfn )
        base_shape();

module pretty_red_arrow() {
    color("red")
    translate([15,0,baspos.y]){
        square( [5,.5], center=true);
        translate([-2,0,0])
        rotate(180)
            circle(2,$fn=3);
        translate([4,0,0])
            text( "joint", 2, valign="center");
        }
    }