#1970s {position:relative}
#1980s {position:relative}

#b1 {position:absolute;top:17;left:39;visibility:hidden}
#b2 {position:absolute;top:17;left:70;visibility:hidden}

#s1a {position:absolute;top:17;left:39;visibility:hidden}
#s1b {position:absolute;top:15;left:0;visibility:hidden}
#s1c {position:absolute;top:15;left:0;visibility:hidden}
#s1d {position:absolute;top:15;left:0;visibility:hidden}
#s1e {position:absolute;top:15;left:0;visibility:hidden}
#s1f {position:absolute;top:15;left:0;visibility:hidden}
#s1g {position:absolute;top:15;left:0;visibility:hidden}
#s1h {position:absolute;top:15;left:0;visibility:hidden}
#s1i {position:absolute;top:15;left:0;visibility:hidden}
#s1j {position:absolute;top:15;left:0;visibility:hidden}

#s2a {position:absolute;top:17;left:70;visibility:hidden}
#s2b {position:absolute;top:15;left:0;visibility:hidden}
#s2c {position:absolute;top:15;left:0;visibility:hidden}
#s2d {position:absolute;top:15;left:0;visibility:hidden}
#s2e {position:absolute;top:15;left:0;visibility:hidden}
#s2f {position:absolute;top:15;left:0;visibility:hidden}
#s2g {position:absolute;top:15;left:0;visibility:hidden}
#s2i {position:absolute;top:15;left:0;visibility:hidden}
#s2j {position:absolute;top:15;left:0;visibility:hidden}
#s2k {position:absolute;top:15;left:0;visibility:hidden}