diff --git a/games/tetris/bast.c b/games/tetris/bast.c
index 4eb1453..fae80ef 100644
--- a/games/tetris/bast.c
+++ b/games/tetris/bast.c
@@ -1,6 +1,118 @@
+#include <inttypes.h>
+#include <stdlib.h>
+#include <string.h>
+#include "piece.h"
+#include "playfield.h"
 #include "bast.h"
 
-int bla()
+
+/***************************
+ * non-interface functions *
+ ***************************/
+
+/* Function:         tetris_bastet_clearColHeights;
+ * Description:      resets the array for the column heights
+ * Argument pBastet: bastet instance whose array should be reset
+ * Return value:     void
+ */
+void tetris_bastet_clearColHeights(tetris_bastet_t *pBastet)
+{
+	int8_t nWidth = tetris_playfield_getWidth(pBastet->pPlayfield);
+	for (int i = 0; i < nWidth; ++i)
+	{
+		pBastet->pColHeights[i] = 0;
+	}
+}
+
+
+/****************************
+ * construction/destruction *
+ ****************************/
+
+/* Function:            tetris_bastet_construct
+ * Description:         constructs a bastet instance for a given playfield
+ * Argument pPlayfield: the playfield to be observed
+ * Return value:        pointer to a newly created bastet instance
+ */
+tetris_bastet_t* tetris_bastet_construct(tetris_playfield_t *pPl)
+{
+	tetris_bastet_t *pBastet =
+		(tetris_bastet_t *) malloc(sizeof(tetris_bastet_t));
+
+	pBastet->pPlayfield = pPl;
+
+	int8_t nWidth = tetris_playfield_getWidth(pBastet->pPlayfield);
+	pBastet->pColHeights = (int8_t*) calloc(nWidth, sizeof(int8_t));
+	tetris_bastet_clearColHeights(pBastet);
+
+	return pBastet;
+}
+
+
+/* Function:         tetris_bastet_destruct
+ * Description:      destructs the given bastet instance
+ * Argument pBastet: the bastet instance to be destroyed
+ * Return value:     void
+ */
+void tetris_bastet_destruct(tetris_bastet_t *pBastet)
+{
+	if (pBastet->pColHeights != NULL)
+	{
+		free(pBastet->pColHeights);
+	}
+
+	free(pBastet);
+}
+
+
+/****************************
+ * bastet related functions *
+ ****************************/
+
+/* Function:         tetris_bastet_construct
+ * Description:      calculates a score for a piece at a given column
+ * Argument pBastet: the bastet instance of interest
+ * Argument pPiece:  the piece to be tested
+ * Argument pnColum: the column where the piece should be dropped
+ * Return value:     score for the given move
+ */
+int16_t tetris_bastet_evalPos(tetris_bastet_t *pBastet,
+                              tetris_piece_t *pPiece,
+                              int8_t nColumn)
 {
-	return 0;
+	int16_t nScore = -32000;
+
+	// modify score based on complete lines
+	int8_t nLines =	tetris_playfield_predictCompleteLines(pBastet->pPlayfield,
+			pPiece, nColumn);
+	nScore += 5000 * nLines;
+
+	// go through every row and calculate column heights
+	tetris_playfield_iterator_t iterator;
+	int8_t nWidth = tetris_playfield_getWidth(pBastet->pPlayfield);
+	int8_t nHeight = 1;
+	uint16_t *pDump = tetris_playfield_predictBottomRow(&iterator,
+			pBastet->pPlayfield, pPiece, nColumn);
+	while (pDump != NULL)
+	{
+		for (int x = 0; x < nWidth; ++x)
+		{
+			if ((*pDump & (0x0001 << x)) != 0)
+			{
+				pBastet->pColHeights[x] = nHeight;
+			}
+		}
+		pDump = tetris_playfield_predictNextRow(&iterator);
+		++nHeight;
+	}
+	// modify score based on predicted column heights
+	for (int x = 0; x < nWidth; ++x)
+	{
+		nScore -= 5 * pBastet->pColHeights[x];
+	}
+
+	// reset column height array for later use
+	tetris_bastet_clearColHeights(pBastet);
+
+	return nScore;
 }
diff --git a/games/tetris/bast.h b/games/tetris/bast.h
index 4aabddc..5ea4f71 100644
--- a/games/tetris/bast.h
+++ b/games/tetris/bast.h
@@ -1,6 +1,55 @@
 #ifndef BAST_H_
 #define BAST_H_
 
-int bla();
+#include <inttypes.h>
+#include "playfield.h"
+#include "piece.h"
+
+/*********
+ * types *
+ *********/
+
+typedef struct tetris_bastet_t
+{
+	tetris_playfield_t *pPlayfield; // the playfield to be examined
+	int8_t *pColHeights;            // array of calculated column heights
+}
+tetris_bastet_t;
+
+
+/****************************
+ * construction/destruction *
+ ****************************/
+
+/* Function:            tetris_bastet_construct
+ * Description:         constructs a bastet instance for a given playfield
+ * Argument pPlayfield: the playfield to be observed
+ * Return value:        pointer to a newly created bastet instance
+ */
+tetris_bastet_t* tetris_bastet_construct(tetris_playfield_t *pPl);
+
+
+/* Function:         tetris_bastet_destruct
+ * Description:      destructs the given bastet instance
+ * Argument pBastet: the bastet instance to be destroyed
+ * Return value:     void
+ */
+void tetris_bastet_destruct(tetris_bastet_t *pBastet);
+
+
+/****************************
+ * bastet related functions *
+ ****************************/
+
+/* Function:         tetris_bastet_construct
+ * Description:      calculates a score for a piece at a given column
+ * Argument pBastet: the bastet instance of interest
+ * Argument pPiece:  the piece to be tested
+ * Argument pnColum: the column where the piece should be dropped
+ * Return value:     score for the given move
+ */
+int16_t tetris_bastet_evalPos(tetris_bastet_t *pBastet,
+                              tetris_piece_t *pPiece,
+                              int8_t nColumn);
 
 #endif /* BAST_H_ */