-int8_t ijcoord_to_corn_idx(int8_t i, int8_t j);
-int8_t xycoord_to_corn_idx(int16_t *x, int16_t *y);
-void init_corn_table(int8_t conf_side, int8_t conf_center);
+/* go from line num1,dir1 to line num2,dir2. Uses trjectory flags
+ * specified as argument and return END_xxx condition */
+uint8_t line2line(uint8_t num1, uint8_t dir1, uint8_t num2,
+ uint8_t dir2, uint8_t flags);