diff --git a/qsr_lib/src/qsrlib_qsrs/__init__.py b/qsr_lib/src/qsrlib_qsrs/__init__.py
index 595f637..5d0955c 100644
--- a/qsr_lib/src/qsrlib_qsrs/__init__.py
+++ b/qsr_lib/src/qsrlib_qsrs/__init__.py
@@ -13,6 +13,7 @@
 from qsr_new_mwe import QSR_MWE
 from qsr_ra import QSR_RA
 from qsr_tpcc import QSR_TPCC
+from qsr_ba import QSR_BA
 # register new qsrs by class name below
 qsrs_registry = (QSR_RCC2,
                  QSR_RCC3_Rectangle_Bounding_Boxes_2D,
@@ -28,4 +29,5 @@
                  QSR_Moving_or_Stationary,
                  QSR_MWE,
                  QSR_RA,
-                 QSR_TPCC)
+                 QSR_TPCC, 
+                 QSR_BA)
diff --git a/qsr_lib/src/qsrlib_qsrs/qsr_ba.py b/qsr_lib/src/qsrlib_qsrs/qsr_ba.py
new file mode 100644
index 0000000..1a3e16e
--- /dev/null
+++ b/qsr_lib/src/qsrlib_qsrs/qsr_ba.py
@@ -0,0 +1,113 @@
+# -*- coding: utf-8 -*-
+from __future__ import print_function, division
+from numpy import isnan
+from qsrlib_qsrs.qsr_dyadic_abstractclass import QSR_Dyadic_1t_Abstractclass
+
+
+class QSR_BA(QSR_Dyadic_1t_Abstractclass):
+    """Block Algebra.
+
+    Members:
+        * _unique_id: "ba"
+        * _all_possible_relations: ("<", ">", "m", "mi", "o", "oi", "s", "si", "d", "di", "f", "fi", "=")
+        * _dtype: "points"
+
+    .. seealso:: For further details about BA, refer to its :doc:`description. <../handwritten/qsrs/ba>`
+    """
+
+    _unique_id = "ba"
+    """str: Unique identifier name of the QSR."""
+
+    _all_possible_relations = ("<", ">", "m", "mi", "o", "oi", "s", "si", "d", "di", "f", "fi", "=")
+    """tuple: All possible relations of the QSR."""
+
+    _dtype = "points"
+    """str: On what kind of data the QSR works with."""
+
+    _inverse_map = {"<": ">", "m": "mi", "o": "oi", "s": "si", "d": "di", "f": "fi",
+                    ">": "<", "mi": "m", "o1": "o", "si": "s", "di": "d", "fi": "f"}
+    """dict: Inverse relations"""
+
+
+    def __init__(self):
+        """Constructor.
+
+        :return:
+        """
+        super(QSR_BA, self).__init__()
+    
+        
+    def _compute_qsr(self, data1, data2, qsr_params, **kwargs):
+        """Compute QSR value.
+
+        :param data1: First object data.
+        :type data1: :class:`Object_State <qsrlib_io.world_trace.Object_State>`
+        :param data2: Second object data.
+        :type data2: :class:`Object_State <qsrlib_io.world_trace.Object_State>`
+        :param qsr_params: QSR specific parameters passed in `dynamic_args`.
+        :type qsr_params: dict
+        :param kwargs: kwargs arguments.
+        :return: Computed QSR value.
+        :rtype: str
+        """
+        
+        bb1 = self.return_bounding_box_3d(data1) 
+        bb2 = self.return_bounding_box_3d(data2)
+        
+        if len(bb1) == 6 and len(bb2) == 6:
+            return ",".join([self.__allen((bb1[0], bb1[3]), (bb2[0], bb2[3])),
+                             self.__allen((bb1[1], bb1[4]), (bb2[1], bb2[4])),
+                             self.__allen((bb1[2], bb1[5]), (bb2[2], bb2[5]))])
+        else:
+            raise ValueError("bb1 and bb2 must have length of 6 (3D) for block algebra")
+
+
+    def return_bounding_box_3d(self, data, xsize_minimal=0, ysize_minimal=0, zsize_minimal=0):  
+        """Compute the 3D bounding box of the object.
+
+        :param data: Object data.
+        :type data: :class:`Object_State <qsrlib_io.world_trace.Object_State>`
+        :param xsize_minimal: If object has no x-size (i.e. a point) then compute bounding box based on this minimal x-size.
+        :type xsize_minimal: positive int or float
+        :param ysize_minimal: If object has no y-size (i.e. a point) then compute bounding box based on this minimal y-size.
+        :type ysize_minimal: positive int or float
+        :param zsize_minimal: If object has no z-size (i.e. a point) then compute bounding box based on this minimal z-size.
+        :type zsize_minimal: positive int or float
+        :return: The 3D coordinates of the closest to origin and farthest from origin corners of the bounding box.
+        :rtype: list of 6 int or float
+        """
+        
+        xsize = xsize_minimal if isnan(data.xsize) else data.xsize
+        ysize = ysize_minimal if isnan(data.ysize) else data.ysize
+        zsize = zsize_minimal if isnan(data.zsize) else data.zsize
+    
+        x1 = data.x - xsize/2 
+        y1 = data.y - ysize/2 
+        z1 = data.z - zsize/2
+        
+        x2 = data.x + xsize/2         
+        y2 = data.y + ysize/2          
+        z2 = data.z + zsize/2 
+        
+        return [x1, y1, z1, x2, y2, z2]         
+            
+
+    def __allen(self, i1, i2):
+        if isnan(i1).any() or isnan(i2).any():  
+            raise ValueError("illegal 'nan' values found")
+
+        if i1[1] < i2[0]:
+            return "<"
+        if i1[1] == i2[0]:
+            return "m"
+        if i1[0] < i2[0] < i1[1] and i2[0] < i1[1] < i2[1]:
+            return "o"
+        if i1[0] == i2[0] and i1[1] < i2[1]:
+            return "s"
+        if i2[0] < i1[0] < i2[1] and i2[0] < i1[1] < i2[1]:
+            return "d"
+        if i2[0] < i1[0] < i2[1] and i1[1] == i2[1]:
+            return "f"
+        if i1[0] == i2[0] and i1[1] == i2[1]:
+            return "="
+        return self._inverse_map[self.__allen(i2, i1)]
\ No newline at end of file