Numerous former RCA manufacturing sites have been reported to be polluted with industrial waste.
A former RCA facility in Taiwan's northern county of Taoyuan (now Taoyuan City) polluted groundwater with toxic chemicals and led to a high incidence of cancer among former employees. The area was declared a toxic site by the Taiwanese Environmental Protection Agency. GE and Thomson spent millions of dollars for cleanup, removing 10,000 cubic yards (7,600 m3) of soil and installing municipal water treatment facilities for neighboring communities. A spokesman for RCA's current owners denied responsibility, saying a study conducted by the Taiwan government showed no correlation between the illnesses and the company's facilities, which shut down in 1991. On April 17, 2015, RCA lost the case and the Taipei District Court (??????) ordered RCA's current owners to compensate its former employees with a total of NT$560 million (approximately USD18.1 million).
A plant in Lancaster, Pennsylvania which RCA operated from the late 1940s to June 1986, released more than 250,000 pounds of 1,1,1-trichloroethane pollutants per year from its exhaust stacks. Tests by the United States Environmental Protection Agency (EPA) in the late 1980s and early 1990s, found the groundwater contaminated by trichloroethylene (TCE) and 1,2-dichloroethylene (1,2-DCE). In 1991 and 1992, contaminants were detected in monitoring wells on the east side of the Conestoga River in Lancaster.
The shallow and deep groundwater aquifers beneath the Intersil Facility in Mountaintop, Pennsylvania, which RCA operated in the 1960s and later sold to Harris Corporation, were found in 1999 to contain elevated levels of volatile organic compounds.
A site in Burlington, Massachusetts which RCA used from 1958 to 1994 to make and test military electronics equipment, generated hazardous waste (VOCs, TCE, toluene, ethylbenzene, and xylenes).
In Barceloneta, Puerto Rico, an RCA-operated plant generated wastes containing chromium, selenium and iron. Four lagoons holding chemical waste drained into the limestone aquifer. Used water from the manufacturing process (process water), containing ferric chloride, was treated onsite to remove contaminants and then was discharged into a sinkhole at the site. The treatment of process water created a sludge that was stored onsite in drying beds and in surface impoundments.
The original Rubik's Cube had no orientation markings on the centre faces (although some carried the words "Rubik's Cube" on the centre square of the white face), and therefore solving it does not require any attention to orienting those faces correctly. However, with marker pens, one could, for example, mark the central squares of an unscrambled Cube with four coloured marks on each edge, each corresponding to the colour of the adjacent face; a cube marked in this way is referred to as a "supercube". Some Cubes have also been produced commercially with markings on all of the squares, such as the Lo Shu magic square or playing card suits. Cubes have also been produced where the nine stickers on a face are used to make a single larger picture, and centre orientation matters on these as well. Thus one can nominally solve a Cube yet have the markings on the centres rotated; it then becomes an additional test to solve the centres as well.
Marking the Rubik's Cube's centres increases its difficulty because this expands the set of distinguishable possible configurations. There are 46/2 (2,048) ways to orient the centres, since an even permutation of the corners implies an even number of quarter turns of centres as well. In particular, when the Cube is unscrambled apart from the orientations of the central squares, there will always be an even number of centre squares requiring a quarter turn. Thus orientations of centres increases the total number of possible Cube permutations from 43,252,003,274,489,856,000 (4.31019) to 88,580,102,706,155,225,088,000 (8.91022).
When turning a cube over is considered to be a change in permutation then we must also count arrangements of the centre faces. Nominally there are 6! ways to arrange the six centre faces of the cube, but only 24 of these are achievable without disassembly of the cube. When the orientations of centres are also counted, as above, this increases the total number of possible Cube permutations from 88,580,102,706,155,225,088,000 (8.91022) to 2,125,922,464,947,725,402,112,000 (2.11024).