How do I increnet loops through quarter and year and generate output for field?

Fields in Opp provide year and quarter. opp was created and number of quarters the opp spans

I need loops that will start with the year (ex 2019) and quarter (ex 2) that the opp was created.

Outer loop starts with the year, 2019.

Inner loop starts with the quarter, say 3. 

The opp spans 5 quarters so i nee dthis to iterate 5 times.

The output for the first iteration should be 2019-Q3 so i can input that value into the first new record.

The next run increments up the quarter from 3 to four and it creates the next record with 2019-Q4.

The next run needs to do two things...Restart the quarter count back to 1 and increment the year up to 2020 for a result of 2020-Q1

And so forth until we have looped the number of times  indicated by the span number.

NOTE I alreadt have the basic loop that creates new records for the correct number of times, I just don't know how to do all this incrementing and creating the incementing output.

Any help out there for a new coder please?
following is the part I am working with 

string created = opportunityList.Quarter_Created_op__c;
                        decimal year = opportunityList.Start_Year__c;
                        decimal quarter = opportunityList.Start_Quarter__c;
                        decimal span = opportunityList.Quarters_Spanned_op__c;
                                
                        //while loop1 increment quarter
                        decimal counter1 = year;
                        while (counter1 < Year + 1)
                        {
                        
                        //while loop2 increment year
                        decimal counter2 = quarter;
                        while (counter2 < quarter + 1)
                        {  
                            
                        counter2++;
                    	}//end while loop2
                        
                        counter1++;
                		}//end while loop1
                        
                            //while loop3 create record process                     	
              				decimal counter3 = span;
                            while (counter3 < span)
                			{
                                
                			Open_Quarter__c oq           = new Open_Quarter__C();
                			Quarter_Number__c qn		 = new Quarter_Number__c();
                			oq.Amount_Per_Quarter_oq__c  = opportunityList.Amount_per_Quarter_op__c;
                			oq.Close_Date_oq__c          = opportunityList.CloseDate;
                			oq.Name            			 = opportunityList.Quarter_Created_op__c;
                			oq.Opportunity_Name_oq__c    = opportunityList.Id;
                			oq.Quarters_Spanned_oq__c    = opportunityList.Quarters_Spanned_op__c;

							createOpenQuarter.add(oq);
                			counter3++;
          					
                            }//end while loop3

Thans much,
Steve