function f1()
{
   global $var1, $var2, $var3, $var4, $var5, $var6;
   ...
}
 
function f2()
{
   global $var1, $var9, $var3, $var7, $var5, $var6;
   ...
}
 
function f3()
{
   global $var11, $var2, $var3, $var14, $var5, $var4;
  ...
}