The very early Meccano parts were 'monochrome' in nickel and brass, the literature did come with colourful covers. The instruction books with models, but certainly the magazine covers of the late twenties come with colourful illustrations of the mechanical wonders of the age.
Included in the instruction book are already a few pages with general engineering mechanisms. Instruction book is actually a bit of a misnomer; these booklets are rather a collection of pictures of models without any instruction on how to build them. Finding out how to construct these models is explicitly left to the ingenuity of the builder, to foster and promote his mechanical prowess.
Included in the larger outfits and also available separately was a booklet containing 'standard mechanisms'. A booklet complete with a wide variety of mechanical functions and how these may be achieved with Meccano parts. Explicitly advertising it as proper mechanical engineering in miniature.
These more complex mechanisms in this booklet fortunately do have descriptions of their workings and some hints on how to construct these.
To offer more inspiration and provide a steady stream of mechanical engineering input, the Meccano company published a monthly magazine. This copy of the March '25 issue has a report on the assembling of a large floating crane, also shown on the front cover.
And e.g. an article on copper. This does have me wondering how riveting this would have been to the intended readership, even then...
Today old issues of the Meccano Magazine are offered for sale online fairly regularly, if wanting to browse an actual paper magazine. To browse and get a feel for the content (with period advertisements); all copies of the Meccano Magazine are available at The Archive. All scanned at very high resolution and freely readable or downloadable as a PDF document.
Just for viewing the colourful covers - well worth a browse :-)