diff --git a/gprMax/cmds_geometry/geometry_objects_read.py b/gprMax/cmds_geometry/geometry_objects_read.py
index 936d7349..6c8efff6 100644
--- a/gprMax/cmds_geometry/geometry_objects_read.py
+++ b/gprMax/cmds_geometry/geometry_objects_read.py
@@ -46,7 +46,7 @@ class GeometryObjectsRead(UserObjectGeometry):
             geofile = self.kwargs['geofile']
             matfile = self.kwargs['matfile']
         except KeyError:
-            logger.exception(self.__str__() + 'requires exactly five parameters')
+            logger.exception(f'{self.__str__()} requires exactly five parameters')
             raise
 
         # Discretise the point using uip object. This has different behaviour
@@ -100,7 +100,7 @@ class GeometryObjectsRead(UserObjectGeometry):
         if round_value((dx_dy_dz[0] / grid.dx) != 1 or 
                        round_value(dx_dy_dz[1] / grid.dy) != 1 or 
                        round_value(dx_dy_dz[2] / grid.dz) != 1):
-            logger.exception(self.__str__() + ' requires the spatial resolution ' +
+            logger.exception(f'{self.__str__()} requires the spatial resolution ' +
                              'of the geometry objects file to match the spatial ' +
                              'resolution of the model')
             raise ValueError
diff --git a/gprMax/cmds_geometry/plate.py b/gprMax/cmds_geometry/plate.py
index cd157604..9881a747 100644
--- a/gprMax/cmds_geometry/plate.py
+++ b/gprMax/cmds_geometry/plate.py
@@ -61,7 +61,7 @@ class Plate(UserObjectGeometry):
             p1 = self.kwargs['p1']
             p2 = self.kwargs['p2']
         except KeyError:
-            logger.exception(self.__str__() + ' 2 points must be specified')
+            logger.exception(f'{self.__str__()} 2 points must be specified')
             raise
 
         # isotropic
@@ -72,7 +72,7 @@ class Plate(UserObjectGeometry):
             try:
                 materialsrequested = self.kwargs['material_ids']
             except KeyError:
-                logger.exception(self.__str__() + ' No materials have been specified')
+                logger.exception(f'{self.__str__()} No materials have been specified')
                 raise
 
         if self.do_rotate:
@@ -86,23 +86,15 @@ class Plate(UserObjectGeometry):
         xf, yf, zf = p2
 
         # Check for valid orientations
-        if xs == xf:
-            if ys == yf or zs == zf:
-                logger.exception(self.__str__() + ' the plate is not specified correctly')
-                raise ValueError
-
-        elif ys == yf:
-            if xs == xf or zs == zf:
-                logger.exception(self.__str__() + ' the plate is not specified correctly')
-                raise ValueError
-
-        elif zs == zf:
-            if xs == xf or ys == yf:
-                logger.exception(self.__str__() + ' the plate is not specified correctly')
-                raise ValueError
-
-        else:
-            logger.exception(self.__str__() + ' the plate is not specified correctly')
+        if (xs == xf
+            and (ys == yf or zs == zf)
+            or (xs != xf
+            and ys == yf
+            and zs == zf)
+            or (xs != xf
+            and ys != yf
+            and zs != zf)):
+            logger.exception(f'{self.__str__()} the plate is not specified correctly')
             raise ValueError
 
         # Look up requested materials in existing list of material instances
@@ -110,7 +102,7 @@ class Plate(UserObjectGeometry):
 
         if len(materials) != len(materialsrequested):
             notfound = [x for x in materialsrequested if x not in materials]
-            logger.exception(self.__str__() + f' material(s) {notfound} do not exist')
+            logger.exception(f'{self.__str__()} material(s) {notfound} do not exist')
             raise ValueError
 
         # yz-plane plate
diff --git a/gprMax/cmds_geometry/sphere.py b/gprMax/cmds_geometry/sphere.py
index 014ec3b0..96694862 100644
--- a/gprMax/cmds_geometry/sphere.py
+++ b/gprMax/cmds_geometry/sphere.py
@@ -48,7 +48,7 @@ class Sphere(UserObjectGeometry):
             p1 = self.kwargs['p1']
             r = self.kwargs['r']
         except KeyError:
-            logger.exception(self.__str__() + ' please specify a point and a radius.')
+            logger.exception(f'{self.__str__()} please specify a point and a radius.')
             raise
 
         # Check averaging
@@ -68,7 +68,7 @@ class Sphere(UserObjectGeometry):
             try:
                 materialsrequested = self.kwargs['material_ids']
             except KeyError:
-                logger.exception(self.__str__() + ' no materials have been specified')
+                logger.exception(f'{self.__str__()} no materials have been specified')
                 raise
 
         # Centre of sphere
@@ -85,7 +85,7 @@ class Sphere(UserObjectGeometry):
 
         if len(materials) != len(materialsrequested):
             notfound = [x for x in materialsrequested if x not in materials]
-            logger.exception(self.__str__() + f' material(s) {notfound} do not exist')
+            logger.exception(f'{self.__str__()} material(s) {notfound} do not exist')
             raise ValueError
 
         # Isotropic case
diff --git a/gprMax/cmds_geometry/triangle.py b/gprMax/cmds_geometry/triangle.py
index 17ab6077..5d8ae17f 100644
--- a/gprMax/cmds_geometry/triangle.py
+++ b/gprMax/cmds_geometry/triangle.py
@@ -70,7 +70,7 @@ class Triangle(UserObjectGeometry):
             up3 = self.kwargs['p3']
             thickness = self.kwargs['thickness']
         except KeyError:
-            logger.exception(self.__str__() + ' specify 3 points and a thickness')
+            logger.exception(f'{self.__str__()} specify 3 points and a thickness')
             raise
         
         if self.do_rotate:
@@ -93,7 +93,7 @@ class Triangle(UserObjectGeometry):
             try:
                 materialsrequested = self.kwargs['material_ids']
             except KeyError:
-                logger.exception(self.__str__() + ' no materials have been specified')
+                logger.exception(f'{self.__str__()} no materials have been specified')
                 raise
 
         p4 = uip.round_to_grid_static_point(up1)
@@ -108,21 +108,21 @@ class Triangle(UserObjectGeometry):
         x3, y3, z3 = uip.round_to_grid(up3)
         
         if thickness < 0:
-            logger.exception(self.__str__() + ' requires a positive value for thickness')
+            logger.exception(f'{self.__str__()} requires a positive value for thickness')
             raise ValueError
 
         # Check for valid orientations
         # yz-plane triangle
-        if x1 == x2 and x2 == x3:
+        if x1 == x2 == x3:
             normal = 'x'
         # xz-plane triangle
-        elif y1 == y2 and y2 == y3:
+        elif y1 == y2 == y3:
             normal = 'y'
         # xy-plane triangle
-        elif z1 == z2 and z2 == z3:
+        elif z1 == z2 == z3:
             normal = 'z'
         else:
-            logger.exception(self.__str__() + ' the triangle is not specified correctly')
+            logger.exception(f'{self.__str__()} the triangle is not specified correctly')
             raise ValueError
 
         # Look up requested materials in existing list of material instances
@@ -130,7 +130,7 @@ class Triangle(UserObjectGeometry):
 
         if len(materials) != len(materialsrequested):
             notfound = [x for x in materialsrequested if x not in materials]
-            logger.exception(self.__str__() + f' material(s) {notfound} do not exist')
+            logger.exception(f'{self.__str__()} material(s) {notfound} do not exist')
             raise ValueError
 
         if thickness > 0: