added more examples, project euler

examples/euler-1.zorth

@@ -0,0 +1,18 @@
+: over swap dup rot rot ;
+: rem over over / * - ;
+
+
+0 1
+begin
+  dup 1000 <
+while
+  dup 3 rem 0 = if
+      dup rot + swap
+  else dup 5 rem 0 = if
+      dup rot + swap
+    else fi
+  fi
+  1+
+repeat
+
+drop .

examples/euler-2.zorth

@@ -0,0 +1,14 @@
+: over swap dup rot rot ;
+: rem over over / * - ;
+
+1 2 
+begin
+  over 4000000 < 
+while
+  over 2 rem 0 = if
+    over mem @ + mem swap !
+  else fi
+  dup rot +
+repeat
+
+mem @ .

examples/euler-3.zorth

@@ -0,0 +1,38 @@
+: over swap dup rot rot ;
+: rem over over / * - ;
+: false 0 ;
+: true 1 ;
+
+: palindrome?
+  mem 0 !
+  dup begin
+    dup 0 >
+  while
+    dup 10 rem mem @ 10 * + mem swap !
+    10 /
+  repeat
+  drop
+  mem @ =
+;
+
+: ans mem 8 + ;
+
+1 begin
+  dup 999 <
+while
+  1 begin
+    dup 999 <
+  while
+    over over *
+    dup palindrome? if 
+      dup ans @ > if ans swap ! else drop fi
+    else 
+      drop 
+    fi
+    1+
+  repeat
+  drop
+  1+
+repeat
+
+ans @ .