
ConstantPad[img,{b_{1}, e_{1}}, ..., c]  pads img by replicating constant c b_{i} times at the beginning and e_{i} times at the end of each list at level i  FixedPad[img,{b_{1}, e_{1}}, ...]  pads img by replicating b_{i}and e_{i} times, respectively,the first and last elements of each list at level i  PeriodicPad[img, {b_{1}, e_{1}}, ... ]  pads img by periodically extending each list at level i with b_{i} elements at the beginning and e_{i} elements at the end  ReflectPad[img,{b_{1}, e_{1}}, ...]  pads img by extending each list at level i with b_{i} elements at the beginning and e_{i} elements at the end with its reflected copy  ZeroPad[img, {b_{1}, e_{1}}, ... ]  pads img by appending b_{i} zeros at the beginning and e_{i}zeros at the end of each list at level i 
List padding functions. Out[3]=  
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MatrixJoin[{{mat_{1}, mat_{2}, ...}, ...}]  returns a matrix by concatenating the corresponding rows and columns of matrices mat_{1}, mat_{2}, ...  MatrixThread[{{mat_{1}, mat_{2}, ...}, ...}]  returns a matrix by threading corresponding entries in matrices mat_{1}, mat_{2}, ...  ColumnThread[mat_{1}, mat_{2}, ...]  returns a matrix by threading the columns in mat_{1}, mat_{2}, ...  RowThread[mat_{1}, mat_{2}, ...]  returns a matrix by threading the rows in mat_{1}, mat_{2}, ... 
Matrix combine, join, and thread functions. Out[6]//MatrixForm=  
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Reflect function. Out[9]//MatrixForm=  
