On 12/31/35 patent 2,026,082 was granted to Parker Brothers. Beginning early January 1936 this patent number was put on all Monopoly games including the rules. These rules appear identical to the late Patent 1,509,312 rules. The only difference I see is on page 4 on later copies. The price of extra money was raised from $.60 to $.75 for slip fininsh money and from $.30 to $.35 for regular money.
Later in 1936 several different sets of rules were used. Each of these sets of rules had different symbols at the top. The sets included the single star, the double star, the double square, two differet double circles, and the double diamond. each varient was for a different set.
The single star was used in the #5. this was still the Copyright 1935 rules with a couple of changes. "For From Three to Seven Players" has been removed from under "RULES" on page 1. The "MONEY" section has also been changed. The distribution of the money has been changed again: one $500, seven $100, two $50, five $20, seven $10, five $5, five $1. The rules also indicate at least $12,000 in the game. Other than this the rules are identical to the late rules above. I believe the star denoted rules for an eight player game.
The double star rules were included in the #9. "(If Eight play, one of the players waits until all others receive their Money, then accepts his in denominations convenientfor the Bank.)" has been removed from the "MONEY" section on page 1. Other than this these rules are identical to those above.
Included in the blue #6 sets was a copyright 1935 double square set of rules. This set includes the line "For from Three to Seven Players" under the word "RULES", and "PLAYING PIECE" replaces "TOKEN (Hat, Shoe, etc.)"(signifying the wooden pieces in this set) on page one. A 1935 double circle set of rules was in the the New Edition black #6. Other than this they are identical to the double star rules above.
On October 1st, 1936 three new sets of rules were copyrighted. These included the double square, the double circle, and the double diamond. All these rules have "RULES FOR 1937" at the top between the symbols. The biggest change in these rules was the new short game rules. "Rules for NEW Short games are shown on separate sheet." is above "RULES" on page one. On the bottom of page four short game rules are still touched on, but direct you to the separate sheet. The short game sheet has rules for two short games on one side and the different versions Monopoly was available in on the other. The picture at the top of the sheet was also changed. The new picture is a sketch of what appears to be a Trade Mark board. The only difference between the double square and double circle rules is in the "PREPARATION" section. The circle rules still refer to "Token" while the square rules refer to "Playing Piece" Both are for from three to seven players. This makes the squares for the blue #6 with wooden playing pieces and the circles for the black #6 with metal tokens. The double diamond set is for from three to eight players and is found in the green #8 edition. Soon after their release "A PARKER TRADING GAME" was added to page one above the patent numbers.
In 1938 the only changes to the rules was "RULES FOR 1937" was removed from the top of each set, the address in New York was changed to 200 Fifth Ave, and the prices for extra money were dropped to $.50 for varnished money and $.25 for regular money. These rules were used until 1940.