It was thought that such an approach would lead to producing large panels, usable for example as wall decor in a hotel lobby or corporate office. In a further development, the researchers used very thin copper sheets in place of the decorative sheet (still overlaying that with the melamine-impregnated top sheet). The overall effect was like a large metal medallion, or a copper sculpture. Many impressive samples emerged from the research lab. The product simulating natural slate proved to be a very popular product and was a leading seller for many years.
These theories speculate that ETA and members of the security forces and national and foreign (Morocco) secret services were involved in the bombings.   Defenders of the claims that ETA participated in some form in the 11 March attacks have affirmed that there is circumstantial evidence linking the Islamists with two ETA members who were detained while driving the outskirts of Madrid in a van containing 500 kg of explosives 11 days before the train bombings.  The Madrid judge Coro Cillán is continuing to hear conspiracy theory cases, including one accusing government officials of ordering the scrapping of the bombed train cars in order to destroy evidence.