Comparing the different versions of bricks with sideways logo.
On the left the UK version of the brick with the sideways logo, made in the Wrexham factory.
Logo: Wide Round O logo.
Mold number: on the short side, probably CA with numbers 1 to 24 and 25 to 48 and ABS with 49 to 72.
Material: CA and ABS
Mold pip: The CA bricks have the mold pip centered on the inside bottom edge, the ABS bricks have the mold pip just above the center on the short side.
On the right the USA/Canada version of the brick with the sideways logo.
Logo: Narrow Round O logo.
Mold number: below the left tube, numbers 1 to 20.
Material: ABS, with the exception of the transparent bricks which are made in CA.
Mold pip: just above the center on the short side.