Consider a single-tape Turing machine that cannot write on its tape, but does have three pebbles on the tape. The pebbles are colored red, green, and blue, and all three are initially on the leftmost tape cell. Each move of this Turing machine works like a standard one (except it cannot write on the tape) with the additional operation of determining which pebbles (if any) are on the tape cell currently being scanned by the head, and optionally moving each of these pebbles one cell to the left or right (pebbles do not have to move in the same direction that the head does, and if there is more than one pebble on the current tape cell, they do not have to more in the same direction). A. Describe how any r. e. set can be accepted by such a Turing Machine. HINT: Simulate a two-counter machine.
B. Suppose that the pebbles are not colored and one cannot tell them apart; is it still possible to accept any r. e. set?

Formatting rows and columns is similar to cell formatting. in an openoffice calc spreadsheet, you can format data entered into rows and columns with the of the rows and columns options. you can insert rows and columns into, or delete rows and columns from, a spreadsheet. use the insert or delete rows and columns option on the insert tab. alternatively, select the row or column where you want new rows or columns to appear, right-click, and select insert only row or only column options. you can hide or show rows and columns in a spreadsheet. use the hide or show option on the format tab. for example, to hide a row, first select the row, then choose the insert tab, then select the row option, and then select hide. alternatively, you can select the row or columns, right-click, and select the hide or show option. you can adjust the height of rows and width of columns. select row and then select the height option on the format tab. similarly, select column, then select the width option on the format tab. alternatively, you can hold the mouse on the row and column divider, and drag the double arrow to the position. you can also use the autofit option on the table tab to resize rows and columns.