diff --git a/Makefile b/Makefile
index 6a05a27..b86e4d1 100644
--- a/Makefile
+++ b/Makefile
@@ -30,6 +30,12 @@ define tgt_template =
    $(1)_BINARYS=$(3)
 endef
 
+define exe_template =
+   $(1)_SOURCES=$(SRC)/$(2)
+   $(1)_OUTPUTS=$$($(1)_SOURCES:$(SRC)/%.c=$(BIN)/%.o)
+   $(1)_BINARYS=$(3)
+endef
+
 define lib_template =
    $(1)_SOURCES=$$(wildcard $(SRC)/$(2)*.c)
    $(1)_HEADERS=$$(wildcard $(SRC)/$(2)*.h)
@@ -40,7 +46,11 @@ endef
 $(eval $(call tgt_template,MAIN,main.c,$(CODEDEFS)/eikyo-main.bin))
 $(eval $(call tgt_template,MFED,mfed.c,$(CODEDEFS_MFED)/eikyo-mfed.bin))
 
+$(eval $(call exe_template,STRH,strh.c,$(BIN)/strh))
+$(eval $(call exe_template,GOL5,golan5.c,$(BIN)/golan5))
+
 $(eval $(call lib_template,GAME,g_,eikyo-game.bin))
+$(eval $(call lib_template,INTR,i_,eikyo-interface.bin))
 $(eval $(call lib_template,RNDR,r_,eikyo-render.bin))
 $(eval $(call lib_template,MISC,m_,eikyo-misc.bin))
 
@@ -49,25 +59,23 @@ MISC_LIBOUTS=$(MISC_SOURCES:$(SRC)/%.c=$(BIN)/%.o)
 MAPS_SOURCES=$(wildcard $(MAPSRC)/*.gmf9)
 MAPS_OUTPUTS=$(MAPS_SOURCES:$(MAPSRC)/%.gmf9=$(MAPBIN)/%.gmf0)
 
-GOL5_SOURCES=$(SRC)/golan5.c
-GOL5_OUTPUTS=$(GOL5_SOURCES:$(SRC)/%.c=$(BIN)/%.o)
-GOL5_BINARYS=$(BIN)/golan5
-
 LIBC_OUTPUTS=$(IR)/libc.ir $(IR)/libGDCC.ir
 LIBC_BINARYS=$(CODEDEFS)/stdlib.bin
 
 .PHONY: clean
 .SECONDARY: $(MISC_LIBOUTS)
 
-all: $(FOLDERS) $(GAME_BINARYS) $(MAIN_BINARYS) $(MFED_BINARYS) $(MISC_BINARYS) $(RNDR_BINARYS) $(LIBC_BINARYS) $(MAPS_OUTPUTS)
+all: $(FOLDERS) $(GAME_BINARYS) $(INTR_BINARYS) $(MAIN_BINARYS) $(MFED_BINARYS) $(MISC_BINARYS) $(RNDR_BINARYS) $(LIBC_BINARYS) $(MAPS_OUTPUTS)
 
 $(GAME_BINARYS): $(GAME_OUTPUTS)
 $(GOL5_BINARYS): $(GOL5_OUTPUTS)
+$(INTR_BINARYS): $(INTR_OUTPUTS)
+$(LIBC_BINARYS): $(LIBC_OUTPUTS)
 $(MAIN_BINARYS): $(MAIN_OUTPUTS)
 $(MFED_BINARYS): $(MFED_OUTPUTS)
 $(MISC_BINARYS): $(MISC_OUTPUTS)
 $(RNDR_BINARYS): $(RNDR_OUTPUTS)
-$(LIBC_BINARYS): $(LIBC_OUTPUTS)
+$(STRH_BINARYS): $(STRH_OUTPUTS)
 
 $(FOLDERS):
 	mkdir -p $@
@@ -87,8 +95,8 @@ $(BIN)/%.o: $(SRC)/%.c $(MISC_HEADERS)
 %.bin:
 	$(GDCC_LD) $(GDCC_LFLAGS) -o $@ $^
 
-$(IR)/%.ir: $(SRC)/%.c $(GAME_HEADERS) $(MISC_HEADERS) $(RNDR_HEADERS)
-	$(GDCC_CC) $(GDCC_CFLAGS) -o $@ $<
+$(IR)/%.ir: $(SRC)/%.c $(GAME_HEADERS) $(INTR_HEADERS) $(MISC_HEADERS) $(RNDR_HEADERS) $(STRH_BINARYS)
+	$(GDCC_CC) $(GDCC_CFLAGS) -DM_fileHash=$(shell bin/strh $<) -o $@ $<
 
 $(LIBC_OUTPUTS):
 	$(GDCC_MAKELIB) $(GDCC_CFLAGS) -o $@ $(basename $(@F))
diff --git a/src/i_gui.c b/src/i_gui.c
new file mode 100644
index 0000000..eb1ab52
--- /dev/null
+++ b/src/i_gui.c
@@ -0,0 +1,55 @@
+// Copyright © 2017 Project Golan, all rights reserved.
+#include "i_gui.h"
+
+#include "m_math.h"
+
+// Static Functions ----------------------------------------------------------|
+
+//
+// I_GUI_auto
+//
+static void I_GUI_auto(I_gictx *g, I_objid id, int xl, int yl, int xu, int yu)
+{
+   if(M_AABBPoint(xl, yl, xu, yu, g->cr.x, g->cr.y)) {
+      g->hot = id;
+      if(g->lc) g->act = id;
+   }
+}
+
+// Extern Functions ----------------------------------------------------------|
+
+//
+// I_GUI_Begin
+//
+void I_GUI_Begin(I_gictx *g)
+{
+   g->hot = 0;
+}
+
+//
+// I_GUI_End
+//
+void I_GUI_End(I_gictx *g)
+{
+   // Set last left/right clicks.
+   g->llc = g->lc;
+   g->lrc = g->rc;
+
+   if(!g->lc && !g->rc)
+      g->act = 0;
+}
+
+//
+// I_GUI_ButtonFId
+//
+bool I_GUI_ButtonFId(I_gictx *g, I_objid id, int x, int y, char const *text)
+{
+   int const xl = x     , yl = y;
+   int const xu = x + 90, yu = y + 30;
+
+   I_GUI_auto(g, id, xl, yl, xu, yu);
+
+   return false;
+}
+
+// EOF
diff --git a/src/i_gui.h b/src/i_gui.h
new file mode 100644
index 0000000..24a4cbc
--- /dev/null
+++ b/src/i_gui.h
@@ -0,0 +1,39 @@
+// Copyright © 2017 Project Golan, all rights reserved.
+#ifndef i_gui_h
+#define i_gui_h
+
+#include "m_types.h"
+#include "i_ui.h"
+
+#include <Doominati.h>
+
+#define I_GUI_button(g, ...) I_GUI_ButtonFId(g, I_lineHash, __VA_ARGS__)
+
+// Extern Functions ----------------------------------------------------------|
+
+void I_GUI_Begin(struct I_gictx *g);
+void I_GUI_End  (struct I_gictx *g);
+
+// Types ---------------------------------------------------------------------|
+
+typedef struct I_gictx
+{
+   __prop begin {call: I_GUI_Begin(this)}
+   __prop end   {call: I_GUI_End  (this)}
+
+   I_objid hot, act;
+
+   DGE_Point2I cr;
+
+   // TODO: make these a bitfield when david adds Bget_W translation
+   bool lc, llc;
+   bool rc, lrc;
+
+   bool open;
+} I_gictx;
+
+// Types ---------------------------------------------------------------------|
+
+bool I_GUI_ButtonFId(struct I_gictx *g, I_objid id, int x, int y, char const *text);
+
+#endif
diff --git a/src/i_ui.h b/src/i_ui.h
new file mode 100644
index 0000000..653923f
--- /dev/null
+++ b/src/i_ui.h
@@ -0,0 +1,11 @@
+// Copyright © 2017 Project Golan, all rights reserved.
+#ifndef i_ui_h
+#define i_ui_h
+
+#define I_lineHash (M_fileHash + __LINE__)
+
+// Types ---------------------------------------------------------------------|
+
+typedef unsigned I_objid;
+
+#endif
diff --git a/src/m_math.c b/src/m_math.c
new file mode 100644
index 0000000..2ff75db
--- /dev/null
+++ b/src/m_math.c
@@ -0,0 +1,14 @@
+// Copyright © 2017 Project Golan, all rights reserved.
+#include "m_math.h"
+
+// Extern Functions ----------------------------------------------------------|
+
+//
+// M_AABBPoint
+//
+bool M_AABBPoint(fixed xl, fixed yl, fixed xu, fixed yu, fixed xp, fixed yp)
+{
+   return xp > xl && yp > yl && xp < xu && yp < yu;
+}
+
+// EOF
diff --git a/src/m_math.h b/src/m_math.h
new file mode 100644
index 0000000..3eb69b6
--- /dev/null
+++ b/src/m_math.h
@@ -0,0 +1,11 @@
+// Copyright © 2017 Project Golan, all rights reserved.
+#ifndef m_math_h
+#define m_math_h
+
+#include "m_types.h"
+
+// Extern Functions ----------------------------------------------------------|
+
+bool M_AABBPoint(fixed xl, fixed yl, fixed xu, fixed yu, fixed xp, fixed yp);
+
+#endif
diff --git a/src/strh.c b/src/strh.c
new file mode 100644
index 0000000..4c5da87
--- /dev/null
+++ b/src/strh.c
@@ -0,0 +1,17 @@
+// Copyright © 2017 Project Golan, all rights reserved.
+#include "m_str.h"
+
+#include <stdio.h>
+
+// Extern Functions ----------------------------------------------------------|
+
+//
+// main
+//
+int main(int argc, char **argv)
+{
+   if(argc) printf("%u\n", M_StrHash(argv[1]));
+   return 0;
+}
+
+// EOF