PHP, 134 Bytes

for($l=$r=($s=$argn)[0];$s[++$i];$l=$s[$i]){$r.=str_pad("",($a=abs($n=ord($l)-ord($s[$i])))<14?$a:26-$a,"><"[$n>0^$a>13])."*";}echo$r;

Testcases

PHP, 139 Bytes

for($l=$r=($s=$argn)[0];$s[++$i];$l=$s[$i]){$r.=str_pad("",$d=min($a=abs(ord($l)-ord($s[$i])),$b=26-$a),"><"[$d<$b^$l<$s[$i]])."*";}echo$r;

Testcases

PHP, 127 Bytes

for($l=ord($r=($s=$argn)[0]);$x=ord($s[++$i]);$l=$x)$r.=str_pad("",($a=abs($n=$l-$x))<14?$a:26-$a,"><"[$n>0^$a>13])."*";echo$r;

Testcases

PHP, 137 Bytes

for($l=$r=($s=$argn)[0];$s[++$i];$l=$s[$i])$r.=str_pad("",$d=min($a=abs(ord($l)-ord($s[$i])),$b=26-$a),"><"[$d<$b^$l<$s[$i]])."*";echo$r;

Testcases

PHP, 139 Bytes

for($l=$r=($s=$argn)[0];$s[++$i];$l=$s[$i]){$r.=str_pad("",$d=min($a=abs(ord($l)-ord($s[$i])),$b=26-$a),"><"[$d<$b^$l<$s[$i]])."*";}echo$r;

Testcases

PHP, 134 Bytes

for($l=$r=($s=$argn)[0];$s[++$i];$l=$s[$i]){$r.=str_pad("",($a=abs($n=ord($l)-ord($s[$i])))<14?$a:26-$a,"><"[$n>0^$a>13])."*";}echo$r;

Testcases

PHP, 139 Bytes

for($l=$r=($s=$argn)[0];$s[++$i];$l=$s[$i]){$r.=str_pad("",$d=min($a=abs(ord($l)-ord($s[$i])),$b=26-$a),"><"[$d<$b^$l<$s[$i]])."*";}echo$r;

Testcases

PHP, 138 Bytes

for($l=$r=($s=$argn)[0];$s[++$i];$l=$s[$i]){$r.=str_pad("",$d=min($a=abs(ord($l)-ord($s[$i]))$b=26-$a),"><"[$d<$b^$l<$s[$i]])."*";}echo$r;

Testcases

PHP, 139 Bytes

for($l=$r=($s=$argn)[0];$s[++$i];$l=$s[$i]){$r.=str_pad("",$d=min($a=abs(ord($l)-ord($s[$i])),$b=26-$a),"><"[$d<$b^$l<$s[$i]])."*";}echo$r;

Testcases