<?php
// $a and $b already known
$a='temple';$b='agile';
$al=strlen($a); $bl=strlen($b);
 $diff=$bl-$al; $offset=abs($diff);
if($diff>=0){
 $twil=$b; $lite=$a;
}else{
$twil=$a;$lite=$b;
}
$tl=strlen($twil); $l=strlen($lite);
 ($tl>$l)?$part1=substr($twil,0,$offset):$part1='';
 ($tl>$l)?$mix1=substr($twil,$offset,$tl):$mix1=$twil;
echo "mix1=$mix1**mix2=$lite**";
$mix1=str_split($mix1); $mix2=str_split($lite);
$mix='';
for($i=0;$i<$l;$i++){
 $mix.=$mix1[$i].$mix2[$i];
}
$answer=$part1.$mix;
echo "**string1= $a**string2= $b";
echo $answer;
?>

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