Hi Offray, you could try this: medMatrix:=Matrix rows: 5 columns: 7. 1 to: medMatrix numberOfRows do: [:row | 1 to: medMatrix numberOfColumns do: [ :column | medMatrix at: row at: column put: 0. Transcript show: row asString, ',', column asString, '|'. ]. Transcript cr. ]."see transcript" medMatrix. "(0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 )" "in scismalltalk:" m2:=DhbMatrix rows: ((1 to: 5) collect:[:i|(Array new:7)]). 1 to: m2 numberOfRows do: [:row | 1 to: m2 numberOfColumns do: [ :column | m2 at: row at: column put: 0. Transcript show: row asString, ',', column asString, '|'. ]. Transcript cr. ]."see transcript" m2. "a DhbVector(0 0 0 0 0 0 0) a DhbVector(0 0 0 0 0 0 0) a DhbVector(0 0 0 0 0 0 0) a DhbVector(0 0 0 0 0 0 0) a DhbVector(0 0 0 0 0 0 0)" werner