The answer to your question is Marsden matting, also known as perferated steel. Marsden matting consisted of steel strips with holes punched through it in rows and U-shaped channels formed between the holes. Hooks were formed along one long edge and slots along the other long edge so that they could be connected to each other. The short edges were straight cut with no holes or hooks. To achieve lengthwise interlocking, the mats were laid in a staggered pattern.

The hooks were usually held in the slots by a steel clip that filled the part of the slot that is empty when the adjacent sheets are properly engaged together. The holes were bent up at their edges so that the beveled edge stiffened the area around the hole. In some situations a T-shaped stake could be driven, at intervals, through the holes to keep the assembly in place on the ground. Sometimes the sheets were welded together.

The typical Marsden matting was the M8 landing mat. A single piece weighed about 66 pounds and was long by wide. The hole pattern for the sheet was 3 holes wide by 29 holes long resulting in 87 holes per mat.