diff --git a/table_demo b/table_demo
index 5069de1..2e72409 100755
--- a/table_demo
+++ b/table_demo
@@ -26,15 +26,25 @@ date_default_timezone_set("America/Los_Angeles");
 //require_once('tcpdf_include.php');
 $outfile = __DIR__ . '/pdflib_table_output.pdf';
 
-// page placement defaults
-$pageTopYPortrait = 750;
-$pageTopYLandscape = 570;
-
+define("PAGE_WIDTH_LETTER", 612);
+define("PAGE_HEIGHT_LETTER", 792);
+define("PAGE_WIDTH_A4", 595);
+define("PAGE_HEIGHT_A4", 842);
 // table params
 $tbl = 0;
 $rowmax = 50;
 $colmax = 5;
-$llx= 50; $lly=50; $urx=550; $ury=800;
+
+// page placement defaults
+$letterPageTopYPortrait = 752;
+$letterPageTopYLandscape = 592;
+$letterPageRightPortrait = 592;
+$letterPageRightLandscape = 752;
+// lower left X, lower left Y, upper right X, upper right Y
+// A4 paper size
+//$llx= 50; $lly=50; $urx=550; $ury=800;
+// Letter paper size
+$llx= 50; $lly=50; $urx=550; $ury=$letterPageTopYPortrait;
 
 // wrap PDFlib usage in a try{} block
 try {
@@ -44,7 +54,9 @@ try {
    $pdf->set_option("errorpolicy=return");
    $pdf->set_option("stringformat=utf8");
    // set up the license key; Linux x86_64
-   $pdf->set_option("license=L900202-010053-139026-P52782-GB5G52");
+   // This will be skipped on Macs
+   if ( php_uname('s') === "Linux" )
+      $pdf->set_option("license=L900202-010053-139026-P52782-GB5G52");
 
    // all paths in 'searchpath' need to be inside curly braces
    // multiple curly-braced paths in $searchpath need to be separated with