A paper path structure, comprising: an input path section for receiving sheets of paper into the paper path structure; an output path section for outputting sheets of paper from the paper path structure; a stack repository for storing a stack of sheets of paper; a flipping device configured for depositing sheets of paper in the stack repository; a first path section controllable to convey sheets of paper to the flipping device; a second path section connected to the input path section and configured to transport sheets of paper to the first path section; a third path section controllable to transport a sheet of paper to the first path section independently from the input path section; wherein the first path section is also controllable to transport sheets of paper to the third path section and wherein the third path section is also controllable to receive sheets of paper from the first path section and to transport the received sheet of paper away from the first path section, characterized in that the paper path structure is configured to: a) transport a sheet from the input path section via the second paper path section to the flipping device, such that the sheet is stacked in an orientation flipped with respect to said sheet's orientation on the input path section; b) transport a sheet from the input path section via consecutively the second and third paper path sections (22, 23) to the output path section, such that said sheet is output to the output path section in an orientation flipped with respect to said sheet's orientation on the input path section; c) transport a sheet from the input path section to the output path section via a fifth paper path section which bypasses the second and third paper path sections (22, 23), such that said sheet is output to the output path section in the same orientation with respect to said sheet's orientation on the input path section; and d) transport a sheet from the input path section via consecutively the fifth and third paper path sections (23, 25) to the flipping device, such that said sheet is stacked in the same orientation with respect to said sheet's orientation on the input path section. an input path section for receiving sheets of paper into the paper path structure; an output path section for outputting sheets of paper from the paper path structure; a stack repository for storing a stack of sheets of paper; a flipping device configured for depositing sheets of paper in the stack repository; a first path section controllable to convey sheets of paper to the flipping device; a second path section connected to the input path section and configured to transport sheets of paper to the first path section; a third path section controllable to transport a sheet of paper to the first path section independently from the input path section; wherein the first path section is also controllable to transport sheets of paper to the third path section and wherein the third path section is also controllable to receive sheets of paper from the first path section and to transport the received sheet of paper away from the first path section, characterized in that the paper path structure is configured to: a) transport a sheet from the input path section via the second paper path section to the flipping device, such that the sheet is stacked in an orientation flipped with respect to said sheet's orientation on the input path section; b) transport a sheet from the input path section via consecutively the second and third paper path sections (22, 23) to the output path section, such that said sheet is output to the output path section in an orientation flipped with respect to said sheet's orientation on the input path section; c) transport a sheet from the input path section to the output path section via a fifth paper path section which bypasses the second and third paper path sections (22, 23), such that said sheet is output to the output path section in the same orientation with respect to said sheet's orientation on the input path section; and d) transport a sheet from the input path section via consecutively the fifth and third paper path sections (23, 25) to the flipping device, such that said sheet is stacked in the same orientation with respect to said sheet's orientation on the input path section. a) transport a sheet from the input path section via the second paper path section to the flipping device, such that the sheet is stacked in an orientation flipped with respect to said sheet's orientation on the input path section; b) transport a sheet from the input path section via consecutively the second and third paper path sections (22, 23) to the output path section, such that said sheet is output to the output path section in an orientation flipped with respect to said sheet's orientation on the input path section; c) transport a sheet from the input path section to the output path section via a fifth paper path section which bypasses the second and third paper path sections (22, 23), such that said sheet is output to the output path section in the same orientation with respect to said sheet's orientation on the input path section; and d) transport a sheet from the input path section via consecutively the fifth and third paper path sections (23, 25) to the flipping device, such that said sheet is stacked in the same orientation with respect to said sheet's orientation on the input path section.